# GCN_circulars

GRB_name: GRB090308A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8962
SUBJECT: GRB 090308: Swift/UVOT Upper Limits
DATE:    09/03/09 18:31:52 GMT
FROM:    Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and P. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 0900308 starting 132 s after
the BAT trigger (Evans et al., GCN Circ. 8948). No optical afterglow
is detected in the initial UVOT exposures at the position
of the X-ray afterglow (Evans and Page, GCN Circ. 8956).
Three-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC)
exposure and subsequent exposures are:

Filter          T_start(s)   T_stop(s)      Exp(s)       Mag 

white (FC)         132          282          147         >21.1
white              570        11390         1102         >22.2
v                  620        17423         1101         >20.6
b                  545         6455          382         >20.8
u                  290         6281          639         >20.7
uvw1               669         6077          399         >20.6
uvm2               644        18019          798         >20.8
uvw2               595        12237         1044         >21.2

The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.11 in the direction of the burst 
(Schlegel et al. 1998).


GRB_name: GRB090308B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8963
SUBJECT: GRB 090308B: Fermi GBM detection
DATE:    09/03/09 21:42:26 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein@msfc.nasa.gov>

A. Goldstein (UAH) and A.J. van der Horst (NASA/MSFC/ORAU)
report on behalf of the Fermi GBM Team: 

"At 17:36:24.70 UT on 08 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090308B (trigger 258226586 / 090308734).
This burst was also independently detected by INTEGRAL SPI-ACS.

The on-ground calculated location, using the GBM trigger 
data, is RA = 22.4, DEC = -58.1 (J2000 degrees, 
equivalent to 01h 30m, 58d 05'), with an uncertainty 
of 2.3 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 50 degrees.

The GBM light curve consists of two peaks with substructure
with a duration (T90) of about 2.11 s (8-1000 keV). 
The time-averaged spectrum from T0-0.25 s to T0+1.53 s is 
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.54 +/- 0.11 and
the cutoff energy, parameterized as Epeak, is 710.3 +/- 100.0 keV
(chi squared 342 for 362 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(3.46 +/- 0.13)E-06 erg/cm^2. The 0.128-sec peak photon flux measured 
starting from T0+0.64 s in the 8-1000 keV band 
is 14.22 +/- 0.91 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090309A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8964
SUBJECT: GRB 090309: Swift detection of a burst
DATE:    09/03/09 23:50:52 GMT
FROM:    David Burrows at PSU/Swift  <dxb15@psu.edu>

P. A. Evans (U Leicester), W. H. Baumgartner (GSFC/UMBC),
D. N. Burrows (PSU), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), W.B Landsman (GSFC),
F. E. Marshall (NASA/GSFC), C. Pagani (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC),
B. A. Rowlinson (U Leicester), T. Sakamoto (NASA/UMBC),
M. H. Siegel (PSU), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU)
report on behalf of the Swift Team:

At 23:29:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090309 (trigger=345945).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 284.981, -25.264 which is 
   RA(J2000) = 18h 59m 55s
   Dec(J2000) = -25d 15' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a peak with a 
with a duration of about 3 sec.  There is a hint of a secondary peak 
around T+25 sec with a duration of 10 sec.  The peak count rate
was ~1400 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 23:30:32.5 UT, 79.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 284.9730, -25.2611
which is equivalent to:
   RA(J2000)  = 18h 59m 53.51s
   Dec(J2000) = -25d 15' 39.8"
with an uncertainty of 3.3 arcseconds (radius, 90% containment). This
location is 28 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.07e+21 cm^-2 (Kalberla et al. 2005). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 81 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle.  The typical upper limit for this image is approximately
white = 19 mag. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.23. 

Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090308A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8965
SUBJECT: GRB 090308: Gemini GMOS Observations
DATE:    09/03/10 05:31:26 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko, A. N. Morgan, D. A. Perley, N. R. Butler, and J. S. Bloom (UC
Berkeley) report on behalf of a larger collaboration:

We have imaged the field of GRB090308 (Evans et al.; GCN 8948) with GMOS
mounted on the Gemini South telescope beginning at approximately 1:38 UT
on the night of 9 March 2009 (~ 7.6 hours after the burst).  Images were
taken in the g', r', i', and z' filters for a total of 300 s in each band.

We find no significant sources inside the revised XRT error circle (Evans
et al.; GCN 8956) to the following limits: g' > 23.8; r' > 24.2; i' >
23.6; z' > 22.5. These limits were calculated using reference stars from
the USNO-B1 catalog and applying the filter transformations of Jordi,
Grebel, and Ammon (A&A 460, 2009).

We do, however, note the presence of an extremely red point source located
several arcseconds southwest of the refined XRT position, and immediately
outside the X-ray position provided by Butler (AJ 133, 2007; see
http://astro.berkeley.edu/~nat/swift/xrt_pos.html).  The coordinates of
this source are (J2000):

 RA: 12:13:59.89
 Dec: -48:49:03.5

This object is detected only in the r', i', and z' filters with
approximate magnitudes: r' = 23.6; i' = 21.6; z' = 20.2 (uncorrected for
Galactic extinction).  While we consider the association unlikely, further
observations are required to determine if this is the afterglow of
GRB090308.

We wish to thank the staff at Gemini Observatory for undertaking these
observations.


GRB_name: GRB090308A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8966
SUBJECT: GRB 090308: GROND observations
DATE:    09/03/10 10:07:05 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

A. C. Updike (Clemson University), C. Clemens, J. Greiner and P. Afonso
(MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090308 (Swift trigger 345777; Evans et al.,
GCN #8948) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla
Observatory (Chile).

Observations started at 00:01 UT on March 9th, 6 hours after the GRB
trigger for 2 hours, and were followed by a second epoch beginning at
07:44 UT and lasting 30 min. They were carried out at an average seeing of
1.7".

The red object just outside the enhanced XRT error circle noted by Cenko
et al. (GCN #8965) is detected in both epochs with no sign of fading.
Therefore, we conclude this is not the afterglow of GRB 090308.

Based on 30 min of our first epoch, we do not detect a source within the
Swift-XRT error circle reported by Evans & Page (GCN #8956) down to (all in
AB system)

 g' > 22.7,
 r' > 22.9,
 i' > 22.6,
 z' > 22.3,
 J > 21.1,
 H > 20.6 and
 K > 19.6

The given limits are derived based on calibrating the images against GROND
zeropoints and 2MASS field stars and are not corrected for the Galactic
foreground extinction corresponding to a reddening of E_(B-V)= 0.114 in the
direction of the burst (Schlegel et al. 1998).


GRB_name: GRB090309A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8967
SUBJECT: GRB 090309, Swift-BAT refined analysis
DATE:    09/03/10 14:02:00 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+362 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090309 (trigger #345945)
(Evans, et al., GCN Circ. 8964).  The BAT ground-calculated position is
RA, Dec = 284.978, -25.274 deg which is 
   RA(J2000)  =  18h 59m 55.5s 
   Dec(J2000) = -25d 16' 42.0" 
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.
 
The mask-weighted light curve shows a single peak starting at T-1 sec, 
peaking around T+1 sec, and ending at T+2 sec.  
T90 (15-350 keV) is 3.0 +- 1.4 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.8 to T+2.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.36 +- 0.33.  The fluence in the 15-150 keV band is 1.3 +- 0.3 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.18 sec in the 15-150 keV band
is 0.9 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/345945/BA/


GRB_name: GRB090306B
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8968
SUBJECT: GRB 090306B: INTEGRAL SPI-ACS light curve 
DATE:    09/03/10 14:23:05 GMT
FROM:    Volker Beckmann at ISDC  <Volker.Beckmann@obs.unige.ch>

V. Beckmann, M. Beck, C. Ferrigno, N. Produit, V. Savchenko (ISDC),
J. Borkowski (CAMK/Torun), D. Gotz (CEA/Saclay), S. Mereghetti 
(INAF/IASF-Milano), A. von Kienlin (MPE) report on behalf of the 
INTEGRAL SPI-ACS GRB team:

GRB 090306B, detected in Swift/BAT slew data (Copete et al. GCN 8944), 
has been independently detected by the SPI Anti-Coincidence
System (ACS) on-board INTEGRAL. The SPI-ACS light curve shows the peak 
of the burst at 2009-03-06T23:07:21.9 with a maximum count-rate of ~390 
counts/50msec. The duration of the GRB is about 14 seconds.

The SPI-ACS light curves are available (both as images and data files)
at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi

The light curves, binned at 50 ms, are derived from 91 independent
detectors with different lower energy thresholds (mainly between 50 keV
and 150 keV) and an upper threshold at about 100 MeV. The ACS response
varies as a function of the GRB incident angle. For these reasons we
caution that the count rates cannot be easily translated into physical
flux units.


GRB_name: GRB090309A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8969
SUBJECT: GRB 090309: Enhanced Swift-XRT position
DATE:    09/03/10 15:00:31 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1230 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 090309, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 284.97425, -25.26099 which is equivalent
to:

RA (J2000): 18h 59m 53.82s
Dec (J2000): -25d 15' 39.6"

with an uncertainty of 2.0 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest position
can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is
described by Goad et al. (2007, A&A, 476, 1401
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090309A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8970
SUBJECT: GRB 090309: Swift-XRT refined analysis
DATE:    09/03/10 15:43:56 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P. A. Evans (U Leicester) reports on behalf of the Swift-XRT team:

We have analysed 5.5 ks of XRT data for GRB 090309 (Evans et al. GCN 
Circ. 8964), from 86 s to 12.4 ks after the BAT trigger. The data are 
entirely in Photon Counting (PC) mode. The enhanced XRT position for 
this burst was given by Goad et al. (GCN. Circ 8969).

The light curve can be modelled with a power-law decay with a decay 
index of alpha=0.38 (+0.08, -0.09).

A spectrum formed from the PC mode data can be fitted with an absorbed 
power-law with a photon spectral index of 2.2 (+/-0.3). The best-fitting 
absorption column is 2.8 (+1.5, -1.1) x 10^21, in excess of the Galactic 
value of 1.1 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to 
observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from 
this spectrum is 4.0 x 10^-11 (6.8 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of 
0.38, the count rate at T+24 hours will be 0.012 count s^-1, 
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.8 x 
10^-13 (8.2 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_products/00345945.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090309B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8971
SUBJECT: GRB 090309B: Fermi GBM detection
DATE:    09/03/10 16:12:00 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the
Fermi GBM Team:

"At 18:25:07.19 UT on 9 March 2009, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 090309B (trigger 258315909 / 090309.767).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 168.4, Dec = -55.0 (J2000 degrees, equivalent to
J2000 11h13m, -55d01'), with a statistical uncertainty of 2.6 degrees
(radius, 1-sigma containment, statistical only; there is additionally
a systematic error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 26 degrees.

The GBM light curve consists of two main peaks, with durations of ~10
and ~25 seconds, and no significant emission above background level in
between for ~25 seconds. The time-averaged spectrum over the two peaks,
from T0-4.1 to T0+5.1 s and from T0+32.8 to T0+54.3 s, is best fit by
a power law with an exponential high-energy cutoff. The index is
-1.52 +/- 0.10 and the cutoff energy, parameterized as Epeak, is
197 +/- 65 keV (chi squared 358 for 360 d.o.f.). The fluence
(8-1000 keV) in this time interval is (4.7 +/- 0.4)E-6 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+37.9s in the
8-1000 keV band is 4.43 +/- 0.17 ph/s/cm^2.

The spectral and temporal analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090305B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8972
SUBJECT: GRB090305B: Fermi GBM detection
DATE:    09/03/10 17:50:24 GMT
FROM:    Colleen A. Wilson at NASA/MSFC/NSSTC  <colleen.wilson@nasa.gov>

Colleen A. Wilson-Hodge (NASA/MSFC)
reports on behalf of the Fermi GBM Team:

"At 01:14:35.72 UT on 05 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090305B (trigger 257908477 / 090305052).

The on-ground calculated location, using the GBM trigger data, is
RA = 155.1, DEC = 68.1 (J2000 degrees, equivalent to 10 h 20 m, 68 d 06'),
with an uncertainty of 5.4 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic error which is
currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 40 degrees.

The GBM light curve shows/consists of a single peak with a duration (T90)
of about 2 s (8-1000 keV). The time-averaged spectrum from T0-0.5 s to
T0+2.5 s is best fit by a Band function with Epeak =  770+/- 230 keV,
alpha = -0.50 +/- 0.17, and beta = -1.9 +/- 0.2.

The event fluence (8-1000 keV) in this time interval is
(2.7 +/- 0.2)E-06 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+0.288 s in the 8-1000 keV band is 11 +/- 2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090309A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8973
SUBJECT: GRB 090309: Swift/UVOT Upper Limits
DATE:    09/03/10 22:03:58 GMT
FROM:    Wayne Landsman at GSFC/SSAI  <wayne.b.landsman@nasa.gov>

W.B. Landsman (NASA/GSFC) and P. Evans (U. Leicester) report on behalf 
of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 090309 starting 82 s after the 
BAT trigger (Evans et al., GCN Circ. 8964). No optical afterglow is 
detected in the initial UVOT exposures at the refined position of the 
X-ray afterglow (Goad et al., GCN Circ. 8969).     An r~19  field star ( 
GSC S9QR039837) is detected 3" from the XRT position.      Three-sigma 
upper limits using the UVOT photometric system (Poole et al. 2008, 
MNRAS, 383, 627) in a 2" radius aperture for the first finding chart 
(FC) exposure and subsequent exposures are:

Filter          T_start(s)   T_stop(s)      Exp(s)       Mag

white (FC)          82          231          147         >21.0
white               82         6136          564         >21.8
v                  624        17530         1317         >20.7
b                  549        23995         1088         >21.4
u                  294        23315         2241         >21.5
uvw1               673        22401         1998         >21.6
uvm2               648        18210         1875         >21.6
uvw2               599        16617         1318         >21.6

The values quoted above are not corrected for the Galactic extinction 
due to the reddening of E(B-V) = 0.23 in the direction of the burst  
(Schlegel et al. 1998).


GRB_name: GRB090307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8974
SUBJECT: GRB 090307A: TAROT Calern observatory optical observations
DATE:    09/03/10 23:27:24 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>

Klotz, A. (CESR-OMP), Gendre, B. (LAM-OAMP),
Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:

We imaged the field of GRB 090307A detected by SWIFT
(trigger 345551) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 373.3s after the GRB trigger
The elevation of the field increased from 16 degrees
above horizon and weather conditions were good.

The first image has a duration of 90.0s.
We do not detect any OT at the XRT position
(Evans GCNC 8946) with a limiting magnitude of:
t0+373.3s to t0+463.3s : R > 16.5

We co-added a series of exposures:
t0+373.3s to t0+1062.0s : R > 18.9

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

N.B. Galactic coordinates are lon=348.7859 lat=+15.1296
and the galactic extinction in R band is ~1.4 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.


GRB_name: GRB090309A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8975
SUBJECT: GRB 090309A: GROND upper limits
DATE:    09/03/11 00:24:38 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

A. C. Updike (Clemson University), C. Clemens, and J. Greiner (MPE
Garching) report on behalf of the GROND team:

We observed the field of the possibly short/hard GRB 090309 (Swift trigger
345945; Evans et al., GCN #8964) simultaneously in g'r'i'z'JHK with GROND
(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI
telescope at La Silla Observatory (Chile).

Observations started at 07:22 UT on March 10th, 7.9 hours after the GRB
trigger and continued for 2.5 hours at an average seeing of 1.5" and an
average airmass of 1.5.

In one hour of stacked exposures, we do not detect a source within the
Swift-XRT enhanced error circle (Goad et al., GCN #8969) down to

g' > 23.4,

r' > 23.8,

i' > 23.2,

z' > 23.0,

J > 21.3,

H > 21.0 and

K > 20.3

The given limits in the AB system are derived based on calibrating the
images against GROND zeropoints and 2MASS field stars and are not
corrected for the Galactic foreground extinction corresponding to a
reddening of E_(B-V)= 0.23 in the direction of the burst (Schlegel et al.
1998).


GRB_name: GRB090205A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8976
SUBJECT: GRB 090205: Zadko Telescope late-time observations
DATE:    09/03/11 03:45:11 GMT
FROM:    David Coward at U of Western Aus.  <coward@physics.uwa.edu.au>

SUBJECT: GRB 090205: Zadko Telescope late-time observations
From: D.M. Coward at UWA

T.P. Vaalsta reports on behalf of the UWA Zadko Telescope Team:

D.M. Coward, T.P. Vaalsta, J. Zadko, A. Imerito, D. Blair, P. Luckas,  
S. Gordon, K. Frost, A. Fletcher (U. of Western Australia)
M. Todd, M. Zadnik (Curtin University)
M. Boer, A. Klotz (TAROT)

The Zadko Telescope team observed the field of GRB 090205
following the report by N. Gehrels and M. Perri (GCN 8525, 09/02/06  
14:46:05 GMT). Observations started at 09/02/06 16:38:29 GMT using an  
iKon DW436BV CAMERA without filters mounted on the F/4 1.0m Zadko  
Telescope about 17.6 hours after the initial burst trigger (GCN 8884).
The GRB field was imaged for a total of 4460s until dawn. In a 1100s  
stacked image, a candidate OA with 23.2(3) white magnitude was  
observed at the enhanced XRT position (GCN 8885). The OA magnitude  
was estimated differentially using nearby nearby USNO-B1 stars as  
references.

The same field was imaged 2 weeks later and the candidate OA was not  
detected.

The UWA Zadko Telescope is currently being commissioned.

This message is quotable in publications


GRB_name: GRB090310A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8977
SUBJECT: GRB090310: Fermi GBM detection
DATE:    09/03/11 16:34:02 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne Rau (MPE) reports on behalf of the Fermi GBM Team:

"At 04:32:49.90 UT on 10 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090310 (trigger 258352371 / 090310189).

The on-ground calculated location, using the GBM trigger
data, is RA = 181.9, DEC = -38.7 (J2000 degrees,
equivalent to 12 h 07 m, -38 d 42 '), with an uncertainty
of 5.7 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 77 degrees.

The GBM light curve shows one bright, narrow peak lasting about 4s
followed by several fainter peaks with a total duration (T90) of
about 125.2 s (8-1000 keV).  

The time-averaged spectrum from T0-0.128 s to T0+3.968 s is
well fit by a power law function with an exponential
high-energy cutoff at 279 +/- 43 keV and  with index -0.65 +/- 0.13
(chi squared 504 for 536 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.15 +/- 0.17)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.128 s in the 8-1000 keV band
is 4.4 +/- 0.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog.

This burst was also independently detected, although untriggered, by 
INTEGRAL SPI-ACS."


GRB_name: GRB090313A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8979
SUBJECT: GRB 090313 OA candidate
DATE:    09/03/13 09:27:18 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

R. Chornock, W. Li, and A. V. Filippenko report on behalf of the KAIT GRB team:

The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory slewed to the
position of GRB 090313 and found a new bright source not present in the DSS:
Coordinates (J2000) 13:13:36.21  +08:05:49.8

The bright moon is hindering follow up, but the source appears to be mag ~16 and
 is a few arcseconds away from a galaxy.


GRB_name: GRB090313A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8980
SUBJECT: GRB 090313: Swift detection of a burst
DATE:    09/03/13 09:34:52 GMT
FROM:    Jirong Mao at INAF-OAB  <jirong.mao@brera.inaf.it>

J. Mao (INAF-OAB), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), C. Guidorzi (U Ferrara),
E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA),
R. Margutti (Univ Bicocca&OAB), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), G. Tagliaferri (INAF-OAB) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:

At 09:06:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090313 (trigger=346386).  The BAT on-board calculated 
location is RA, Dec 198.397, +8.107 which is 
   RA(J2000) = 13h 13m 35s
   Dec(J2000) = +08d 06' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a broad series
of multiple peaks from approximately T-10 to T+40.  The peak count rate
was ~1300 counts/sec (15-350 keV), at ~4 sec after the trigger.  Since 
this was an image trigger, the light curve shows only rather weak peaks. 
We will have more information upon receipt of the BAT event data 
in a few hours. 

Due to a Moon observing constraint, Swift cannot slew to the BAT position
until 16:45 UT. There will thus be no prompt XRT or UVOT data for this trigger. 

Burst Advocate for this burst is J. Mao (jirong.mao AT brera.inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090313A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8981
SUBJECT: GRB 090313: Swift detection of a burst
DATE:    09/03/13 09:35:31 GMT
FROM:    Jirong Mao at INAF-OAB  <jirong.mao@brera.inaf.it>

J. Mao (INAF-OAB), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), C. Guidorzi (U Ferrara),
E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA),
R. Margutti (Univ Bicocca&OAB), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), G. Tagliaferri (INAF-OAB) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:

At 09:06:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090313 (trigger=346386).  The BAT on-board calculated 
location is RA, Dec 198.397, +8.107 which is 
   RA(J2000) = 13h 13m 35s
   Dec(J2000) = +08d 06' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a broad series
of multiple peaks from approximately T-10 to T+40.  The peak count rate
was ~1300 counts/sec (15-350 keV), at ~4 sec after the trigger.  Since 
this was an image trigger, the light curve shows only rather weak peaks. 
We will have more information upon receipt of the BAT event data 
in a few hours. 

Due to a Moon observing constraint, Swift cannot slew to the BAT position
until 16:45 UT. There will thus be no prompt XRT or UVOT data for this trigger. 

Burst Advocate for this burst is J. Mao (jirong.mao AT brera.inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090309A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8982
SUBJECT: GRB 090309, Swift-BAT lag analysis
DATE:    09/03/13 09:58:16 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

T. Sakamoto (GSFC/UMBC), J. P. Norris, T. N. Ukwatta (GWU/GSFC),  
S. D. Barthelmy (GSFC), N. Gehrels (GSFC), M. Stamatikos (GSFC/ORAU)  
(for the Swift-BAT team): 
 
For GRB 090309 (Evans et al. GCN Circ. 8964), we are unable to determine  
if this is a short or long burst.  The reasons are as follows:  (1) the  
spectral lag is 0.044 +/- 0.16 sec (between the 50-100 and 15-25 keV).   
(2) The T90 duration is 3.0 +- 1.4 sec (Palmer et al. GCN Circ. 8967)
which is midway between the two T90 distributions.  (3) The photon index 
is 1.36 +/- 0.33 (Palmer et al. GCN Circ. 8967) is also in the middle of 
the short and hard distributions (Figure 13 of Sakamoto et al., ApJS, 175, 179).


GRB_name: GRB090313A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8983
SUBJECT: GRB 090313, GROND observations
DATE:    09/03/13 10:34:51 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose@tls-tautenburg.de>

A. C. Updike (Clemson University), S. Klose (Tautenburg), C. Clemens
and J. Greiner (MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090313 (Swift trigger 346386; Mao et al. 
2009, GCN 8980) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 
2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla 
Observatory (Chile).

Observations started at 09:13 UT on March 13, 7 minutes after the GRB 
trigger. We confirm that the afterglow candidate reported by Chornock et 
al. (GCN 8979) is bright in all bands.

We measure the following preliminary magnitudes at a mean time of about 10 
minutes after the burst (Vega mags):

J = 14.0 +/- 0.1
H = 13.1 +/- 0.1
K = 12.3 +/- 0.1

calibrated against 2MASS field stars. Astrometry gives RA, DEC (J2000) = 
13:13:36.21, +08:05:49.2 (+/- 0.5 arcsec). As already noted by Chornock 
et al., the afterglow is close to a bright galaxy.

These are preliminary data. Data reduction is in progress.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8984
SUBJECT: GRB 090313: SDSS object underlying the optical afterglow position
DATE:    09/03/13 13:26:03 GMT
FROM:    Edo Berger at Harvard  <eberger@cfa.harvard.edu>

E. Berger (Harvard) reports:

"Inspection of archival Sloan Digital Sky Survey images reveals a faint
(and apparently extended) object near the position of the optical
afterglow (GCN 8979) of GRB 090313 (GCN 8980).  The object is located at:
 RA = 13:13:36.08
 DEC = 08:05:51.06 (J2000)
which is 2.3" away from the optical afterglow position provided by
Chornock et al. (GCN 8979).  The SDSS model magnitudes of this object are:
 g = 22.8+/-0.3
 r = 21.6+/-0.16
 i = 21.1+/-0.18
 z = 20.7+/-0.4

A much brigher galaxy is located 17.8" away from the optical afterglow
position at:
 RA = 13:13:35.29
 DEC = 08:05:38.54 (J2000)
which we consider to be the galaxy mentioned by Chornock et al. (given its
brightness).  The SDSS model magnitudes of this galaxy are:
 u = 17.07+/-0.01
 g = 16.02+/-0.01
 r = 15.57+/-0.01
 i = 15.32+/-0.01
 z = 15.14+/-0.01

A direct determination of the afterglow redshift is required in order to
determine which of the two objects is the host galaxy."


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8985
SUBJECT: GRB 090313: Sustained optical brightness
DATE:    09/03/13 13:45:27 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, W. Li, R. Chornock, and A. V. Filippenko (UC Berkeley) 
report on behalf of the KAIT GRB team:

We continued observing the position of the optical afterglow (Chornock 
et al., GCN 8979) of GRB 080313 (Mao et al., GCN 8980) with the Katzman 
Automatic Imaging Telescope (KAIT) in unfiltered and I-band images 
lasting until 2.9 hours after the trigger.  In spite of significant 
contamination due to scattered light from the full moon 20 degrees away, 
we continue to (marginally) detect the afterglow in 30-second unfiltered 
and 120-second I-band exposures with a magnitude of I = 17.7 +/- 0.4 
(calibrated relative to nearby USNO standards) at this time.

Given the usually bright late-time optical afterglow, the equatorial and 
nearly anti-sun position, and the possibility of an association with the 
  bright nearby galaxy (the second object mentioned in Berger et al., 
GCN 8984, which has a spectroscopic redshift of z=0.0235 according to 
SDSS), and the unclear high-energy classification of this object 
(Sakamoto et al., GCN 8982) we strongly encourage continued follow-up in 
spite of the presence of the nearby moon.

[GCN OPS NOTE(13mar09): Per author's request, please see GCN 8988
that explains the mistaken sakamoto reference  and the high-energy statement
in the last sentence, as explained in the corerction GCN 8988.]


GRB_name: GRB090313A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8986
SUBJECT: GRB 090313: Swift-BAT refined analysis
DATE:    09/03/13 13:48:31 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), J. Mao (INAF-OAB), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090313 (trigger #346386)
(Mao, et al., GCN Circ. 8980).  The BAT ground-calculated position is
RA, Dec = 198.400, 8.086 deg, which is 
   RA(J2000)  =  13h 13m 36.0s 
   Dec(J2000) = +08d 05' 10.7" 
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 15%.
 
The mask-weighted light curve shows emission starting before T-100 sec
at which time the burst location came into the BAT FOV during a pre-programmed
target slew.  BAT triggered on the peak starting at ~T-20 sec, peaking
at ~T+10 sec, and ending at ~T+90 sec.  T90 (15-350 keV) is 78 +- 19 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-21.3 to T+66.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.91 +- 0.29.  The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+4.86 sec in the 15-150 keV band
is 0.8 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/346386/BA/


GRB_name: GRB090306B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8987
SUBJECT: GRB 090306B: Confirmation of the X-ray afterglow
DATE:    09/03/13 13:51:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Swift has performed follow-up observations of the BAT Slew Survey GRB
090306B (Copete et al, GCN Circ. 8944), gathering 4 ks of data in the
interval T0+484 ks to T0+555 ks. The X-ray source reported by Evans et
al. (GCN Circ 8947) is no longer detected, with a 3-sigma upper limit of
1.9e-3  counts/sec. We thus confirm that it was the afterglow of GRB
090306B.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090313A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8988
SUBJECT: GRB 090313: Sustained optical brightness (correction)
DATE:    09/03/13 13:55:10 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley (UC Berkeley) reports:

In the preceding circular reporting on the continued optical brightness 
at ~3 hours, the reference to Sakamoto et al. (GCN 8982) is in error. 
That circular addresses GRB 090309, not GRB 090313.  As is clear in 
Sakamoto et al. (GCN 8986), this event is clearly a long GRB (T90 = 78 
+- 19 sec).  I apologize for any confusion.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8989
SUBJECT: GRB 090313: Faulkes Telescope North observations
DATE:    09/03/13 18:53:56 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), A. Melandri, I. A. Steele (Liverpool JMU),
A. Gomboc (U. Ljubljana), D. Bersier, C.J. Mottram, C.G.  Mundell,
R.J. Smith (Liverpool JMU), P. O'Brien, N. Bannister,
N. Tanvir (U. Leicester) on behalf of a large collaboration report:

The 2-m Faulkes Telescope North (Hawaii) automatically reacted to the
Swift burst GRB 090313 (trigger=346386, Mao et al. GCN 8980).

Observations started about 168 s after the trigger time with filters
BRi. We confirm the detection of the optical counterpart (Chornock et 
al. GCN 8979,
Updike et al. GCN 8983, Perley et al. GCN 8985).
The afterglow magnitude was observed to rise and peak around
1.3 ks post burst, followed by a rapid decay out to ~ 10 ks.
Further observations suggest a subsequent flattening.

Filter  Tmid(s)    Exposure(s)    Mag
------------------------------------------------
   R        880           60      16.12 +/- 0.07
   R       1260          120      15.60 +/- 0.05
   R      12290          300      18.20 +/- 0.20
------------------------------------------------

Magnitudes are calibrated with respect to the nearby USNOB1 star
13:13:35.789 +08:05:24.11 assuming its catalogue value of R2=17.08.
Further observations are going to be attempted.


GRB_name: GRB090313A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8990
SUBJECT: GRB 090313: Swift/UVOT upper limits
DATE:    09/03/13 22:50:45 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P.Schady (MSSL-UCL) S.T. Holland (CRESST/GSFC/USRA) and J. Mao (INAF-OAB) 
report on behalf of the Swift/UVOT team:

The Swift/UVOT began observing the field of GRB 0903013 once it came out 
of Moon constraint, 27ks after the BAT trigger (Mao et al., GCN Circ. 
8980). There is no afterglow detection in any of the b, u or uvw1 UVOT 
filter observations taken at the optical afterglow position reported by 
Chornock et al. (GCN 8979), although by coadding all filters into a single 
exposure, a source is marginally detected at the 2-sigma level.

The 3-sigma upper limits for GRB090313 within each UVOT filter are as 
follows:

Filter      T_mid(hrs)   Exp(s)  3-sig Mag UL
u             7.98        223      > 20.81
b             7.82        885      > 21.36
uvw1          7.57        886      > 21.32

where Tmid is the weighted mean time of the observations. The values 
quoted above are not corrected for the Galactic extinction due to the 
reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 
1998).


GRB_name: GRB090313A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8991
SUBJECT: GRB 090313: Swift-XRT refined analysis
DATE:    09/03/13 23:00:22 GMT
FROM:    Jirong Mao at INAF-OAB  <jirong.mao@brera.inaf.it>

J. Mao & R. Margutti (INAF-OAB) report on behalf of the Swift-XRT team:

We have analysed 2 ks of XRT data for GRB 090313 (Mao et al. GCN Circ. 
8980),
from 26.8 ks to 28.6 ks after the BAT trigger. All the data were taken in
Photon Counting (PC) mode. Using 2038 s of XRT Photon Counting mode data
and 1 UVOT image, we find an astrometrically corrected X-ray position 
(using
the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 198.40130, 8.09730 which is equivalent to:

RA (J2000):  13 13 36.30
Dec (J2000): +08 05 50.4

with an uncertainty of 1.8 arcsec (radius, 90% confidence).

The optical candidate (Chornock et al. GCN 8979 and Updike et al. GCN 
8983) lies within
the XRT error circle.

The lightcurve can be modeled as a single power-law with an index around 
5.4. Given the present
data set the value of this parameter is affected by a large uncertainty.

The PC mode spectrum can be fit with an absorbed simple power-law, with 
a photon index
of 2.12  0.33 and an absorbing column density of 1.29  0.97 e21 cm-2,  
in excess of the Galactic
value of 2.10e20 cm-2 (Kalberla et al. 2005). The counts to observed 
(unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum is 5.1e-11 (5.9e-11) erg 
cm-2 count-1.

Given the very uncertain power-law decay index, no firm prediction of 
the lightcurve can be made.

The results of the automatic XRT analysis are available online at
http://www.swift.ac.uk/xrt_products/00346386.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8992
SUBJECT: GRB 090313: Ongoing plateau phase
DATE:    09/03/13 23:39:20 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (ESO), J. Gorosabel, A. Sota, A.J. Castro-Tirado
(IAA-CSIC) report on behalf of a larger collaboration:

We have observed the field of GRB 090313 (Mao et al. GCNC 8980)
with the 1.5m OSN telescope (Granada, Spain) starting on  22:29 UT
(13.4 hours after the burst). Our I-band images show that the optical
afterglow reported by Chornock et al. (GCNC 8979) is still bright.
Preliminary photometry yields I=17.7+/- 0.3. This would imply that the
plateau phase reported by Perley et al. (GCN 8985) is still ongoing,
half a day later.

Further observations are encouraged


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8993
SUBJECT: GRB 090313 optical observations
DATE:    09/03/14 01:47:12 GMT
FROM:    AAVSO GRB Network at AAVSO  <matthewt@aavso.org>

Markku Nissinen (Varkaus, Finland) reports to the AAVSO High Energy Network
the following optical observations of GRB 090313 (Chornock, Li, and
Filippenko, GCN #8979; Mao et al., GCN #8980):

Markku Nissinen reports the detection of the optical counterpart of GRB
090313 using the GRAS-04 telescope sited in Mayhill, NM, USA.  A number
of unfiltered observations with varying exposure times were made using
the 0.25-meter telescope with an SBIG ST8XE CCD camera; observations began
approximately 1 hour post burst.  The afterglow was detected in all frames
with astrometric positions matching those given by Chornock, Li, and
Filippenko (GCN #8979) and Updike et al (GCN #8983) to within positional
errors.

The following unfiltered magnitudes were obtained from the observations
using USNO-A2.0 U0975_07146255 (R magnitude = 15.9) as the comparison:

   obs midpoint(UT)   exptime  mag(CR)   mag.err

2009-03-13 10:14:41  360 sec  16.5  +/-  0.3  (3 x 120 sec)
2009-03-13 10:27:59  300 sec  16.7  +/-  0.3
2009-03-13 10:39:53  600 sec  16.9  +/-  0.3

A FITS image of the 300-second observation is available at the following URL:
ftp://ftp.aavso.org/grb/MarkkuNissinen_GRB090313_2454904.28608_.fits

The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.


GRB_name: GRB090313A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8994
SUBJECT: GRB 090313: Gemini-S redshift
DATE:    09/03/14 05:45:25 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

R. Chornock, D. A. Perley, S. B. Cenko, J. S. Bloom, B. Cobb (UC 
Berkeley), and J. X. Prochaska (UCO/Lick) report:

We began a spectroscopic integration on the afterglow of GRB 090313 
(Chornock et al., GCN 8979; Mao et al., GCN 8980) using Gemini-South 
(GMOS) starting at 04:20 UT on 2009-03-14, approximately 19 hours after 
the trigger.  We conducted a series of two exposures of 600 seconds each 
using the R400 grating, covering a wavelength range of approximately 
3900 to 8140 Angstroms.  Additional exposures are in progress.

We detect transitions corresponding to C IV, Al II, O I, Si II, Si IV, 
and Fe II, as well as a broad absorption feature which we associate with 
Lyman-alpha, at a common redshift of z=3.375.  We also detect Si II* at 
this redshift, identifying this as the redshift of the GRB.  While 
ruling out an association with the bright nearby SDSS galaxy, this 
redshift suggests an extraordinary late-time afterglow luminosity.  We 
continue to encourage sustained late-time follow-up of this event, which 
given its continued brightness (Perley et al., GCN 8985; de Ugarte 
Postigo et al., GCN 8992) is likely to continue to be observable to 
small-aperture telescopes for an extended period of time.

We thank the Gemini staff for conducting these observations.


GRB_name: GRB090313A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8995
SUBJECT: GRB 090313 - PAIRITEL NIR detections
DATE:    09/03/14 06:35:06 GMT
FROM:    Adam Morgan at PSU/Swift-UVOT  <qmorgan@gmail.com>

A. N. Morgan, J. S. Bloom, D. A. Perley (UC Berkeley),  and D. Starr
(UCB, LCOGT) report:

We observed the optical afterglow of GRB 090313 (Mao et al. 2009, GCN
8980) with PAIRITEL beginning at 2009-03-13 09:39 UT, 31 minutes after
the Swift Trigger.  We detect the afterglow (Chornock et al., GCN
8979) in all 111 47-second mosaics of 7.8 second simultaneous
exposures in the J, H, and Ks taken throughout the night.

Preliminary lightcurves indicate a shallowing of the temporal decay
rate during the 3.5 hours over which the afterglow was observed.  The
preliminary photometry yields:

post_burst
t_mid (hr) exp(s)  filt  mag   merr
0.941      1883    J     14.7  0.1
0.941      1883    H     13.8  0.1
0.941      1883    K     12.8  0.1

2.302      2331    J     15.6  0.1
2.302      2331    H     14.6  0.1
2.302      2331    K     13.8  0.1

3.512      1860    J     15.9  0.1
3.512      1860    H     15.4  0.1
3.512      1860    K     14.1  0.1

No correction for Galactic extinction has been made to the above
reported values.  Further observations are being taken tonight.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8996
SUBJECT: GRB 090313: Zadko Telescope observations
DATE:    09/03/14 09:04:51 GMT
FROM:    David Coward at U of Western Aus.  <coward@physics.uwa.edu.au>

SUBJECT: GRB 090313: Zadko Telescope observations
FROM: D.M Coward at UWA

T. Vaalsta and D.M. Coward report on behalf of the Zadko Telescope Team.

T. Vaalsta, D. Coward, J. Zadko, A. Imerito, D. Blair, R. Burman,
P. Luckas, S. Gordon, K. Frost, A. Fletcher, J. Moore
(University of Western Australia)
M. Todd, M. Zadnik (Curtin University)
M. Boer, A. Klotz (TAROT)

The Zadko telescope started observing the field of
GRB 090313 (trigger=346386, Mao et al. GCN 8980)
4.26h after the Swift trigger, under difficult conditions due to
significant sky brightness from the Moon.

Preliminary photometry of unfiltered images
taken with an iKon DW436BV camera show a slow
decay of the optical afterglow:


Time(s)     Magnitude
-------------------------------------
21356       18.02 +/- 0.08
22662       18.49 +/- 0.10
24115       18.49 +/- 0.10
26028       18.62 +/- 0.09
27890       18.78 +/- 0.09
29834       18.84 +/- 0.12

Magnitudes were calibrated with respect to the
nearby USNOB1 star 0980-0264084 (13 13 36.392
+08 04 47.69). The optical afterglow is close
to a 16.37 magnitude galaxy (PGC 1338801).

The Zadko Telescope is currently being commissioned.
This message is quotable in publications


Dr David Coward
Senior Research Fellow
School of Physics
University of Western Australia
Crawley WA 6009

Tel: +61 8 6488 4563
Mobile 0423981240
Fax: +61 8 6488 1170


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8997
SUBJECT: GRB 090313: Gemini-S photometry
DATE:    09/03/14 10:38:18 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley (UC Berkeley) reports on behalf of a larger collaboration:

Following our spectroscopic integration on the optical afterglow of GRB
090313 (GCN 8994), we acquired one 60s frame in each of g, r, i, and z
filters using Gemini-S (GMOS) in imaging mode between 05:11 and 05:18 UT
(20.07 hours after the burst).  We report the following magnitudes:

g = 21.62 +/- 0.08
r = 20.12 +/- 0.03
i = 19.50 +/- 0.05
z = 19.03 +/- 0.05

The optical SED is well-fit assuming a moderate (A_V ~< 0.4) amount of
SMC-like dust extinction.  The presence of a 2175 A dust feature is
strongly ruled out by the z-band measurement.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8998
SUBJECT: GRB 090313: TAROT La Silla observatory optical detection
DATE:    09/03/15 00:38:51 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>

Klotz, A. (CESR-OMP), Gendre, B. (LAM-OAMP),
Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:

We imaged the field of GRB 090313 detected by Swift
(trigger 346386) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 104s after the GRB trigger
The elevation of the field decreased from
37 degrees above horizon and weather conditions
were good but the moon was at 20 deg.

The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect the OT reported by Chornock et al. (GCNC 8979)
with a limiting magnitude of:
t0+104s to t0+164s : R > 15.3

The second image is 30.0s exposure in tracking mode:
t0+186s to t0+216s : R > 16.6

We co-added a series of exposures.
The OT is detected:
t0+186s to t0+421s : R = 17.1

All images are unfiltered.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

This message may be cited.


GRB_name: GRB090313A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  8999
SUBJECT: GRB 090313: Light curve steepening
DATE:    09/03/15 04:39:47 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (ESO), J. Gorosabel, A. Sota,
A.J. Castro-Tirado (IAA-CSIC), S. McBreen (Univ.
College Dublin) and M.R. Zapatero-Osorio (IAC)
report on behalf of a larger collaboration:

We continued the observations of the afterglow (Chornock
et al. GCNC 8979) of GRB 090313 (Mao et al. GCNC 8980)
from the 1.5m OSN telescope at Sierra Nevada Observatory
(Granada, Spain) in I-band, the 0.8m IAC80 telescope at
Teide Observatory (Tenerife, Spain) in R-band and the
2.5m NOT telescope in nIR bands.

The observations show how the light curve maintains its
brightness until at least 0.8341 days after the burst,
where our last image from OSN shows the afterglow at
I=17.9+/-0.2. This is still stable as compared to the
report of Perley et al. (GCNC 8985) 0.12 days after
the burst and our previous report (de Ugarte Postigo
et al. GCNC 8992) 0.56 days after the burst. We note
that our new magnitude is somehow brighter than the one
reported by Perley et al. at a similar epoch (GCNC
8997). This could be due to a calibration issue. We are
using USNO-B1.0 stars as reference.

From the IAC80 we observe the burst during the plateau
0.6482 days after the burst at a magnitude of 19.1+/-0.1.

At NOT telescope we clearly detect the bright afterglow in
J and Ks bands with NOTCAM 0.7989 days after the burst at a
magnitude of Ks=15.2+/-0.3. We used 2MASS for the calibration,
which is the main source of uncertainty in this value.

Observations continued the following night, where we see a
strong drop in the magnitude of the afterglow, which can be
detected at I=20.2 +/- 0.4, 1.5547 days after the burst,
indicating the presence of a break in the light curve.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9000
SUBJECT: GRB 090313: WSRT Radio Observations
DATE:    09/03/15 16:16:34 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) and A.P. Kamble (University of
Amsterdam) report on behalf of a larger collaboration:

"We observed the position of the GRB 090313 afterglow at 4.9 GHz with the
Westerbork Synthesis Radio Telescope at March 14 21.06 UT to March 15
7.27 UT, i.e. 1.50 - 1.92 days after the burst (GCN 8980).
We do not detect a radio source at the position of the optical counterpart
(GCN 8979). The three-sigma rms noise in the map around that position is
114 microJy per beam. The formal flux measurement for a point source at the
position of the optical counterpart is 26 +/- 38 microJy.

We would like to thank the WSRT staff for scheduling and obtaining these
observations."


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9001
SUBJECT: GRB 090313: Additional Gemini-S photometry
DATE:    09/03/15 20:00:06 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, S. B. Cenko, J. S. Bloom, W. Li, and B. E. Cobb (UC 
Berkeley) report:

We conducted additional imaging observations of the optical afterglow of 
  GRB 090313 (GCN 8979, GCN 8780) consisting of 2x90 seconds in g, r, i, 
and z filters on Gemini-S (GMOS) between 08:39 and 08:58 UT on 
2009-03-15 (47.7 hours after the burst).  At this time we measure an 
afterglow magnitude (calibrated using SDSS stars in the field) of r = 
21.77 +/- 0.05, confirming the steepening in the decay reported by de 
Ugarte Postigo et al. (GCN 8999).  The amount of fading relative to our 
first epoch (GCN 8997) is consistent across all four filters. We measure 
an average decay index (F ~ t^-alpha) of alpha=1.77 over this interval.


GRB_name: GRB090313A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9002
SUBJECT: GRB 090313: MITSuME Okayama observation
DATE:    09/03/16 09:58:21 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 090313 (Mao et al. GCN 8980) with
the optical three-color (g', Rc and Ic) CCD camera attached to
the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2009-03-14 14:27:51 UT (29.34 hours
after the alert). We detected a point source at the position of
the X-ray - optical - IR afterglow (Chornock and Filippenko GCN
8979; Mao et al. GCN 8991; Updike et al. GCN 8983; Vaalsta et al.
GCN 8996; de Ugarte Postigo et al. GCN 8992, GCN 8999; Perley
GCN 8997; Perley et al. GCN 9001) in Ic band. Photometric result
is listed below. We used GSC2.3 catalog for flux calibration.

Mid-UT                Td           Exp.Time      Ic
-------------------------------------------------------------
2009-03-14 16:30:24   31.3775 hr   60sec x 171   19.3 +/- 0.2
-------------------------------------------------------------

Our result and previous reports (Vaalsta et al. GCN 8996; Perley
GCN 8997; de Ugarte Postigo et al. GCN 8999) show that the
afterglow maintained its brightness from 10 hours to 30 hours
after the burst. de Ugarte Postigo et al. (GCN 8999) and Perley
et al. (GCN 9001) reported steep decline of the I band magnitude
of the object after our observation. Thus the break point of the
light curve may exist at around 31 hours after the burst.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9003
SUBJECT: Radio detection of GRB090313
DATE:    09/03/16 10:17:38 GMT
FROM:    Guy Pooley at MRAO, Cambridge, UK  <ggp1@cam.ac.uk>

Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics, 
University of Cambridge) reports:

We detected GRB 090313 in an observation with the
AMI Large Array in the frequency range 14.5 to 17.5 GHz.

The observation was on 2009 Mar 16 from 02h00m to 04h24m (2d 18h after the 
burst: Mao et al, GCN 8980). We measured a flux density of 820 microJy with 
an rms noise of 71 microJy, at a position 13h13m36.0s +08d05'47", 
consistent with the optical position (Chornock et al GCN8979). 
The resolution is 63"x24" at p.a. 24deg.  

This message may be quoted.


GRB_name: GRB090305B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9004
SUBJECT: GRB090305B: MASTER-net prompt optical short burst observations 
DATE:    09/03/16 10:21:16 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, 
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parhomenko,
  Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinski, I.Zalognikh, T.Kopytova
Ural State University, Kourovka


S.Yazev, K.Ivanov
Irkutsk State University

There are 6 MASTER Very Wide Field cameras located at Kislovodsk and Irkutsk 
with common FOW = 6000 square degrees (http://observ.pereplet.ru/).

One of the four  MASTER Very Wide Field Cameras located at Kislovodsk
(D=50 mm, 4x1000 square degrees, 11 Mpx) has observed  ~80% 1-sigma Fermi 
error box  (Colleen A. Wilson-Hodge, GCN 8972) with 1s exposure
during  all night: 7 hours befoure, during and 1 hours after GRB Time 
without time gap between images.


Our unfiltered images are calibrated relative to Tycho stars (V).
The magnitude limit of the each emage is  ~9.5 m at the edge of FOW.

We do not detect OT inside part of the error box  (Colleen A. Wilson-Hodge, GCN 
8972)  brighter than 9.2 mag before and after trigger time.
We  conclude in case that GRB inside our FOW that:

1). the optical fluence during the short 2 s GRBurst is limited by

                       ~<= 1 x 10E-8 erg/cm_2

excluding possible  host galaxy absorbtion.

The event fluence (8-1000 keV) in this time interval is
(2.7 +/- 0.2)E-06 erg/cm^2 (Colleen A. Wilson-Hodge, GCN
8972).

So:

2).  Optical-Fluence/Gamma-Fluence(8-1000 keV) ~ < 1/100

The same ratio for long GRB080319B is

Optical-Fluence/Gamma-Fluence(8 - 1000 keV) ~ 1/140

(Naked Eye GRB, Racusin, Karpov et al., Nature, vol.455, 183, 2008).


The film of our observations (from 10 s before and 15 s after GRB time) is 
available at

http://observ.pereplet.ru/images/GRB090305B/GRB090305B_full2.gif

White & black circles are the 1-sigma & 3-sigma+systematic (2 degrees) 
error boxes correspondingly. Black rectangle is the IPN error box (Palshin et al., private 
communication).

The FOWs of the 2 cameras are available at
http://observ.pereplet.ru/images/GRB090305B/FOW090305.png

The reduction is continued.

The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9005
SUBJECT: GRB 090313: detection with CARMA in 3mm band
DATE:    09/03/16 15:21:35 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

D. C.-J. Bock (CARMA), P. Chandra (RMC), D. A. Frail (NRAO), and S. R. 
Kulkarni (Caltech)
 report on behalf of a larger collaboration:

"We observed the field of view of GRB 090313 (GCN 8980) with the Combined
Array for Research in Millimeter-Wave Astronomy (CARMA) at a frequency of
92.5 GHz at the mean observation time of 2009 March 14, 0930 UT, within a
day of detection by the Swift. We detect the GRB at the KAIT optical 
afterglow
position (GCN 8979) with a flux density of 4.0+/-0.6 mJy.  The map rms 
noise
is 0.17 mJy.

We acknowledge excellent support from the staff and observers at CARMA."


GRB_name: GRB090313A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9006
SUBJECT: Further Swift/UVOT observations of GRB 090313
DATE:    09/03/16 20:55:05 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P.Schady (MSSL-UCL), F.E.Marshall (NASA/GSFC) and J. Mao (INAF-OAB) report 
on behalf of the Swift/UVOT team:

Following on from GCN 8990 (Schady et al.), we report on Swift/UVOT 
observations of GRB 090313 for all optical and ultraviolet filters. A 
fading source is detected in the v filter and marginally in the b-band 
filter at a position consistent with the optical afterglow reported by 
Chornock et al. (GCN 8979). These observations are in agreement with the 
spectroscopic redshift z=3.375 (Chornock et al., GCN 8994).

The magnitudes and 3-sigma upper limits for GRB 090313 within each 
co-added UVOT filter are as follows:

Filter   T_mid (hrs)    Exp (s)   Mag/3-sigma UL
v          11.0          551      20.10 +/- 0.30 (3.6 sigma)
b          11.2          770      21.50 +/- 0.38 (2.8 sigma)
u          8.1           1024     > 21.44
uvw1       8.6           1771     > 21.78
uvm2       9.3           886      > 21.22
uvw2       10.9          886      > 21.58

where T_mid is the weighted mean time of the observations. The values 
quoted above are not corrected for the Galactic extinction due to the 
reddening of E(B-V)  = 0.03 in the direction of the burst (Schlegel et al. 
1998). All photometry is on the UVOT photometry system described in Poole 
et al. (2008, MNRAS, 383, 627).

In addition, we note an error in GCN 8990 (Schady et al.), where we 
mistakenly labelled the results for the u filter as b and vice versa.


GRB_name: GRB090313A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9007
SUBJECT: Further radio observation of GRB 090313
DATE:    09/03/17 09:17:34 GMT
FROM:    Guy Pooley at MRAO, Cambridge, UK  <ggp1@cam.ac.uk>

Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics,
University of Cambridge) reports further to GCN9003:

We observed the field of GRB 090313 again with the
AMI Large Array in the frequency range 14.5 to 17.5 GHz.
The observation was on 2009 Mar 16 23h51m to Mar 17 02h50m 
(3d 18h after the burst). 

We measured a flux density of 860 microJy with an rms
noise of 75 microJy, at a position consistent with that reported in
GCN9003. The spectrum over that frequency band is consistent with 
a spectral index of zero, but is not well constrained because of 
the relatively narrow bandwidth and faint flux.

Since the flux density has not changed significantly, while 
radio detections of GRBs at this early stage are often highly variable,
the association of this source with the GRB is currently not confirmed.


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9008
SUBJECT: GRB 090313, SMARTS optical/IR observations
DATE:    09/03/18 01:06:29 GMT
FROM:    Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>

B. E. Cobb (UC Berkeley) reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained
optical/IR imaging of the error region of GRB 090313 (GCN 8980, Mao
et al.) over four epochs (with UT mid-exposure times of: 2009-03-14 04:27,
2009-03-14 06:55, 2009-03-15 06:30 & 2009-03-17 05:07). Total
summed exposure times for each observation amounted to
36 minutes in R and 30 minutes in J.

The GRB afterglow (e.g. GCN 8979, Chornock et al., GCN 8983, Updike et
al. and GCN 8985, Perley et al.) appears in our imaging to be fading 
rapidly after ~19 hours post-burst:

mid-exposure time
(hours post-burst)   R mag           J mag
19.33                19.70+/-0.04    17.38+/-0.15
21.81                19.90+/-0.04    17.62+/-0.15
45.38                21.57+/-0.12    18.91+/-0.16
92.01                > 22.5          > 19.8

These preliminary magnitudes are calibrated using Landolt standard
stars in the optical and a 2MASS star in the IR.

This rapid fading follows the initial plateau phase that was reported by 
Perley et al. (GCN 8985) and de Ugarte Postigo et al. (GCN 8992).  This 
fading is consistent with the light curve break noted by de Ugarte 
Postigo et al. (GCN 8999), though the break appears to occur in this 
imaging somewhat earlier than suggested by Yoshida et al. (GCN 9002).


GRB_name: GRB090315A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9009
SUBJECT: IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
DATE:    09/03/18 23:52:04 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@ssl.berkeley.edu>

K. Hurley and T. Cline, on behalf of the Mars Odyssey
and Konus GRB teams,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team,

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, and D. Frederiks, 
on behalf of the Konus-Wind team,

K. Yamaoka, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada,
T. Murakami, and K. Makishima on behalf of the Suzaku WAM team,

S. Barthelmy, J. Cummings, N. Gehrels, and H. Krimm, on behalf of
the Swift-BAT team,

J. Goldsten, on behalf of the MESSENGER NS GRB team, 

E. Costa, E. Del Monte, G. Di Cocco, I. Donnarumma, Y. Evangelista, M.
Feroci, F. Fuschino, M. Galli, C. Labanti, I. Lapshov, F. Lazzarotto,
M. Marisaldi, L. Pacciani, M. Rapisarda, and P. Soffitta,  on behalf of the
AGILE MCAL and SuperAGILE teams, and

C. Navia, on behalf of the Tupi collaboration, report:

GRB090315 was observed by Odyssey (HEND and GRS), MESSENGER (GRNS),
Konus-Wind, AGILE (MCAL and SuperAGILE, although the spacecraft was in
the SAA and the background was high; the event was outside the field of
view of SuperAGILE), Suzaku (WAM), and Swift (BAT, but outside the
coded field of view) at 04:12:56 UT.  The burst had a fluence of
several times 10^-5 erg cm^-2  and  a duration of about 9 s (detailed
spectral information will be provided in a separate GCN Circular).  We
have triangulated it to the following preliminary, 3 sigma error box,
whose area is 0.8 sq. deg.

-----------------------------------------------
       RA(2000), deg            Dec(2000), deg
-----------------------------------------------
Center:
  142.641 (09h 30m 34s)   -27.556 (-27d 33' 21")
Corners:
  140.759 (09h 23m 02s)   -26.958 (-26d 57' 28")
  140.936 (09h 23m 45s)   -27.257 (-27d 15' 25")
  144.531 (09h 38m 07s)   -28.062 (-28d 03' 43")
  144.339 (09h 37m 21s)   -27.782 (-27d 46' 57")
-----------------------------------------------

This error box may be improved.

The Tupi ground-based muon telescope (Augusto et al., Phys. Rev. D 77,
123008, 2008) which was pointed in the direction of the burst
registered a significant increase in the count rate in a single 10 s
long bin which included the time of the burst, while a second telescope
whose field of view did not include the burst did not.  (The count
rates and fields of view have been posted at
ssl.berkeley.edu/ipn3/090315).  The muon energy threshold is ~0.1 GeV,
corresponding to primary photons above 10 GeV.  Thus we believe that
the energy spectrum of this GRB extended at least into the multi-GeV
energy range.


GRB_name: GRB090315A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9010
SUBJECT: Konus-Wind observation of GRB 090315
DATE:    09/03/19 11:42:37 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The long GRB 090315 localized by IPN (Hurley et al., GCN
9009) triggered Konus-Wind at T0=15180.047 s UT (04:13:00.047).

As observed by Konus-Wind the burst
had a fluence of 2.10(-0.30, +0.32)x10^-5 erg/cm2,
and a 64-ms peak flux measured from T0+5.920 s
of 5.56(-1.33, +1.38)x10^-6 erg/cm2/s
(both in the 20 keV - 5 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+14.080 s) can be fitted (in the 20 keV - 5 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.55(-0.15, +0.19),
the high energy photon index beta = -2.62(-0.91, 0.34),
the peak energy Ep = 247 +/- 33 keV (chi2 = 84.8/73 dof).

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090315_T15180/


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9011
SUBJECT: GRB090313: radio detection with the VLA
DATE:    09/03/19 15:40:15 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

D. A. Frail (NRAO), and P. Chandra (RMC) report on behalf of a larger 
collaboration:

"We observed the field of view of GRB 090313 (GCN 8980) with the Very 
Large Array (VLA) in 8.46 GHz frequency on 2009 March 19.23 UT. We 
detect a radio source at position (J2000) RA 13:13:36.189, Dec 
08:05:49.75, which is within 0.3" of the KAIT optical afterglow position 
(GCN 8979). The GRB flux density at 8.46 GHz band is 269+/-31 uJy.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9012
SUBJECT: GRB 090313: VLT spectroscopy
DATE:    09/03/19 22:51:47 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

C. C. Thoene (INAF-OAB), P. D'Avanzo (Univ. Bicocca & INAF-OAB), D.
Fugazza (INAF-OAB), A. de Ugarte Postigo (ESO), V. D'Elia, S. Piranomonte
(INAF-OAR), S. Covino, S. Campana (INAF-OAB), G. Chincarini (Univ.
Bicocca) report, on behalf of the MISTICI collaboration:

We observed the optical afterglow of GRB 090313 (Chornock et al. GCN 8979;
Mao et al. GCN 8980) with the ESO VLT about 1.9 days after the burst with
the FORS2 camera in spectroscopic mode. We took 4 exposures of 20 min each
with the 600I grism covering the range 6800-9300 Angstrom with a
resolution of R=1500.

While we confirm the redshift reported by Chornok et al. (GCN 8994), we
also report the detection of a broad double absorption feature around
observed lambda 7830 and 7840 angstrom that does not fit any transition at
the GRB redshift (z = 3.375). This double feature can be interpreted as Mg
II 2796,2803, each consisting of 2 velocity components with a separation
of about 300 km/s, and could be a signature of an intervening system at
z ~ 1.8. We cannot confirm the presence of Mg I 2852 at z = 1.8 due to the
possible overlap with Mg I 1827 absorption at the redshift of the GRB.

We acknowledge excellent support from the ESO staff, in particular Yuri
Beletsky.


GRB_name: GRB090315A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9013
SUBJECT: GRB 090315: Suzaku WAM observation of the prompt emission
DATE:    09/03/20 15:48:22 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka@phys.aoyama.ac.jp>

 N. Kodaka, W. Iwakiri, M. Tashiro, Y. Terada, Y. Urata, A. Endo,
 K. Onda, K. Morigami, T. Sugasahara (Saitama U.), T. Enoto, K. Nakazawa, 
 K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka (Aoyama Gakuin U.), 
 M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa, 
 T. Tamagawa (RIKEN), T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira, 
 Y. Hanabata (Hiroshima U.), E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, 
 N. Ohmori, K. Kono, H. Hayashi (Univ. of Miyazaki), S. Hong (Nihon U.),
 N. Vasquez (Tokyo Tech.), on behalf of the Suzaku WAM team, report:

 The long, IPN localized GRB 090315 (Hurley et al., GCN 9009)
 triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
  energy range of 50 keV - 5 MeV at 04:12:57.218 UT (=T0).
 The observed light curve shows a multi-peaked structure starting at
 T0-0.5 s, ending at T0+8.5 s, with a duration (T90) of about 6.9 seconds.
 The fluence in 100 - 1000 keV was 1.10(-0.06,+0.15) x 10^-5 erg/cm^2.
 The 1-s peak flux measured from T0+5.5 s was 4.9(-1.3,+0.4) photons/cm^2/s
 in the same energy range.

 Preliminary result shows that the time-averaged spectrum from
 T0-0.5 s to T0+8.5 s is well fitted by a power-law with exponential
 cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha       1.62 (-0.51,+0.33), and
  Epeak       320 (-100,+90) keV (chi^2/d.o.f. = 31.6/24).

 All the quoted errors are at statistical 90% confidence level,
 in which the systematic uncertainties are not included.

 The light curves for this burst will be soon available at:
  http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090313A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9015
SUBJECT: X-shooter observations of GRB 090313
DATE:    09/03/23 02:58:03 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo, S. DOdorico (ESO PI), J. Vernet, A. Modigliani,
S. Ramsay from ESO Commissioning team;
S. Covino (INAF Brera), H. Flores (Obs. Paris), J. Fynbo, J. Hjorth
(NBI/DARK, U. Copenhagen) and R.A.M.J. Wijers (Astr. Institute,
U. Amsterdam) from the X-shooter GRB team;
F. Hammer (Obs. Paris), L. Kaper (Astr. Institute, U. Amsterdam),
P. Kjaergaard (NBI, U. Copenhagen), S. Randich (INAF Arcetri) as
X-shooter PIs;
P.J. Groot (Radboud Univ. Nijmegen) from the X-shooter Science Team.

On March 15.22 UT we initiated observations of GRB 090313 (Chornock
et al., GCNC 8979; Mao et al., GCNC 8980) with X-shooter at the ESO
Melipal telescope of the Paranal Observatory. X-shooter is the first
of the second-generation VLT instruments and includes three
Echelle spectrographs, the Ultraviolet/Blue (UVB), the Visible (VIS)
and the Near Infrared (NIR), which combined provide a fixed spectral
format and cover in one shot the spectral range 3000 - 24000 A at
medium spectral resolution (R = 4000 - 10000 depending on the arm
and slit width). The mean epoch of the observation was 45.3 hours
after the burst, when the afterglow had faded to R ~ 21.6 (Perley et
al. GCNC 9001; Cobb et al. GCNC 9008). In the 4 x 1500 s combined
spectrum we clearly detect continuum above 5580 A with several
absorption lines; below this, the signal is dominated by background
emission produced by the nearby Moon (90 % illumination at 37 deg
from the field). The spectrum indicates an absorption redshift
of z = 3.3721  0.0004 (consistent with that measured by Chornock et
al., GCNC 8994 and Thoene et al., GCNC 9012) through the detection of
Si II (1304.5), C II (1334.5), Si IV (1393.8), Si IV (1402.8), Si II
(1526.7), C IV (1548.2,1550.8), Fe II (1608.5), Fe II (1611.2),
Al III (1854.7), Al III (1862.8), Zn II (2062.6), Fe II (2600.1),
Mg II (2796.3, 2803.5) and Mg I (2853.0). The intervening system
identified by Thoene et al. (GCNC 9012) is resolved into multiple
components through the detection of Fe II, Mg II and Mg I lines with
its main absorption at redshift 1.800. A further system at z = 1.959
shows Fe II, Mg II and Mg I absorption.

The spectra of GRB 090313 will be made public on the ESO web as other
data of scientific relevance obtained during the commissioning of the
instrument.

[GCN OPS NOTE923mar09): Per author's request, the Groot-author's
affiliation was changed.]


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9016
SUBJECT: GRB 090313: WSRT Radio Detection
DATE:    09/03/23 05:45:35 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) and A.P. Kamble (University of
Amsterdam) report on behalf of a larger collaboration:

"We reobserved the position of the GRB 090313 afterglow at 4.9 GHz with
the Westerbork Synthesis Radio Telescope at March 20 18.89 UT to March 21
6.88 UT, i.e. 7.41 - 7.91 days after the burst (GCN 8980).
We detect a radio source with a flux density of 165 +/- 30 microJy at the
position of the optical counterpart (GCN 8979).

We would like to thank the WSRT staff for scheduling and obtaining these
observations."


GRB_name: GRB090313A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9017
SUBJECT: Further 15GHz observations of GRB090313
DATE:    09/03/23 12:34:06 GMT
FROM:    Guy Pooley at MRAO, Cambridge, UK  <ggp1@cam.ac.uk>

Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics,
University of Cambridge) reports:

Further observations of the field of GRB090313 have been made with the
AMI Large Array in the frequency range 14.5 to 17.5 GHz.

Including those already reported in GCN 9003 and 9007, after minor
recalibration, the flux densities measured were

2009 Mar 16.13  800 +- 80 microJy
2009 Mar 17.06  882 +- 77
2009 Mar 18.05  815 +- 129
2009 Mar 20.16  718 +- 97
2009 Mar 23.05  655 +- 69

Observations lasted between 1 and 3 h, and the resolution is
approximately 60x25 arcsec. The position is consistent with that
of the optical transient (Chornock et al GCN8979).

This message may be quoted.


GRB_name: GRB090320A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9018
SUBJECT: GRB 090320A: Fermi GBM detection
DATE:    09/03/23 14:53:00 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne Rau (MPE) reports on behalf of the Fermi GBM Team:


"At 10:01:46 UT on 20 March 2009, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 090320A (trigger 259236108 / 090320.418).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 242.4, Dec = -51.9 (J2000 degrees, equivalent to
J2000 16h 10m, +/-51d 54'), with a statistical uncertainty of 10.8 degrees
(radius, 1-sigma containment, statistical only; there is additionally
a systematic error which is currently estimated to be 2 to 3 degrees).

The GBM light curve shows a single peak  with a duration (T90)
of about 10 s (8-1000 keV). The reliability for T90 is low due to strong 
background fluctuations.

The angle from the Fermi LAT boresight is 60 degrees.
Since the source is weak, the time-averaged spectrum is poorly 
constrained."


GRB_name: GRB090319A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9019
SUBJECT: GRB 090319: Fermi GBM detection
DATE:    09/03/23 15:35:25 GMT
FROM:    Vandiver Chaplin at UAH/Fermi-GBM  <chapliv@email.uah.edu>

V.Chaplin (UAH) reports on behalf of the Fermi GBM Team:

"At 14:55:35.22 UT on 19 MARCH 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090319 (trigger 259167337 / 090319622).

The on-ground calculated location, using the GBM trigger
data, is RA = 274.6, DEC = -11.4 (J2000 degrees,
equivalent to 18h 18m, -11d 24'), with an uncertainty
of 3.0 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 27 degrees.

The GBM light curve consists of two ~6 s peaks at
about T0+13 and T0+30 s on top of a smooth component,
with a duration (T90) of about 67.7 s (8-1000 keV).
The time-averaged spectrum from T0-6.144 to T0+37.889 s is
best fit by a power law function with an exponential
high energy cutoff.  The power law index is 0.90 +/- 0.10 and
the cutoff energy, parameterized as Epeak, is 187.3 +/- 20.4 keV
(chi squared 463.25 for 467 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(7.47 +/- .53)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+13.312 s in the 8-1000 keV band
is 3.85 +/- 0.12 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090320B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9020
SUBJECT: GRB 090320B: Fermi GBM detection.
DATE:    09/03/23 15:39:21 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat@nasa.gov>

P. N. Bhat (UAH) 
report on behalf of the Fermi GBM Team:

At 19:13:46.10 UT on 20 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090320B (trigger 259269228 / 090320801).

The on-ground calculated location, using the GBM trigger
data, is RA = 183.8, DEC = 57.6 (J2000 degrees,
equivalent to 12 h 15.3 m, 57 d 33 '), with an uncertainty
of 9.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 101 degrees.

The GBM light curve shows one main pulse with several
weaker trailing pulses with a duration (T90) of about 52 s (8-1000 keV).
The time-averaged spectrum from T0-7.4 s to T0+52 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.1 +/- 0.3 and
the cutoff energy, parameterized as Epeak, is 72 +/- 14 keV

(chi squared 255 for 237 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.1 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 8-1000 keV band
is 0.12 +/- 0.04 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090323A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9021
SUBJECT: Fermi GBM and LAT detections of GRB 090323
DATE:    09/03/23 21:24:41 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

Masanori Ohno (ISAS/JAXA), Sara Cutini (ASDC), Julie McEnery (NASA/GSFC),
Jim Chiang (SLAC/KIPAC), Elmar Koerding (AIM/Saclay) report on behalf of
the Fermi LAT team, and Alexander van der Horst (NASA/MSFC/ORAU) reports
on behalf of the Fermi GBM team.

"At 00:02:42.63 UT on 23 March 2009, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB 090323 (trigger 259459364 / 090323002).
The GBM light curve consists of multiple peaks and has a duration of
~150 seconds.

The Fermi Large Area Telescope (LAT) has significantly, with more than
5 sigma, detected this GRB. Emission was observed in the LAT up to a few
GeV. The high-energy emission commences several seconds after the GBM
trigger time, and we see marginal evidence in the LAT that it continues
for up to a couple of kilo-seconds.

The best LAT on-ground localization is found to be (RA,Dec=190.69, 17.08)
with a 68% (resp. 90%) containment radius of 0.09 deg (resp. 0.14,
statistical), and a systematic error less than 0.1 deg. The GBM on-ground
localization is consistent with this LAT localization within statistical
and systematic uncertainties.

We further report that the Fermi Observatory executed a maneuver following
this trigger and tracked the burst location for the next 5 hours, subject
to Earth-angle constraints.

Further analysis is ongoing.

The points of contact for this burst are Masanori Ohno (LAT,
ohno@astro.isas.jaxa.jp) and Alexander van der Horst (GBM,
Alexander.J.VanDerHorst@nasa.gov).

The Fermi LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product
of an international collaboration between NASA and DOE in the U.S.
and many scientific institutions across France, Italy, Japan and Sweden.

This message can be cited."


GRB_name: GRB090320C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9022
SUBJECT: GRB 090320C: Fermi GBM Detection
DATE:    09/03/23 21:38:57 GMT
FROM:    Vandiver Chaplin at UAH/Fermi-GBM  <chapliv@email.uah.edu>

V.Chaplin (UAH) reports on behalf of the Fermi GBM Team:

"At 01:05:10.53 UT on 20 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090320C (trigger 259203912 / 090320045).

The on-ground calculated location, using the GBM trigger
data, is RA = 108.2, DEC = -43.3 (J2000 degrees,
equivalent to 7h 13m, -43d 18'), with an uncertainty
of 15.0 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 40 degrees.

The GBM light curve has a duration (T90) of about 4 s (8-1000 keV),
with a peak at about T0-2 seconds.

Since the source is weak, the time-averaged spectrum is poorly  
constrained."


GRB_name: GRB090323A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9023
SUBJECT: IPN triangulation of GRB090323
DATE:    09/03/23 23:21:41 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@ssl.berkeley.edu>

K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB
team, 

A. von Kienlin, G. Lichti, and A. Rau, on behalf of the
INTEGRAL SPI-ACS GRB team, and

V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM
team, report:

MESSENGER (GRNS) and INTEGRAL (SPI-ACS) have so far observed
GRB090323 (Ohno et al. GCN 9021).  We have triangulated this
burst to a preliminary annulus centered at RA, Dec = 149.980, +11.232,
whose radius is 39.826 +/- 0.286 degrees (3 sigma).  This
annulus intersects the GBM localization, and the LAT localization
lies 0.007 degrees from the center line of this annulus.  A 
map has been posted at ssl.berkeley.edu/ipn3/090323 showing the
GBM contours and best-fit position, the IPN annulus, and the LAT
best-fit position and error circle.

The IPN localization may be improved.


GRB_name: GRB090323A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9024
SUBJECT: GRB 090323: Possible XRT Counterpart
DATE:    09/03/24 03:31:40 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>

J. Kennea (PSU), P. Evans and M. Goad (U Leicester) report on behalf of 
the Swift/XRT Team:

At 19:27UT on March 23rd, 2009, Swift began a TOO observation of the 
Fermi/LAT error circle of GRB 090323 (GCN #9021). Ground analysis of the 
initial data finds an uncatalogued point source inside the LAT error 
circle. Currently only one orbit of data has been downlinked so it is not 
possible to determine if the source is fading.

Using 1137 s of XRT Photon Counting mode data and 2 UVOT images, we find 
an astrometrically corrected X-ray position (using the XRT-UVOT alignment 
and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 
190.70940, 17.05390 which is equivalent to:

RA (J2000):  12 42 50.26
Dec (J2000): +17 03 14.2

with an uncertainty of 2.7 arcsec (radius, 90% confidence). This position 
is 1.9 arcminutes from the LAT on-ground localization given in GCN #9021.

This position may be improved as more data are received. The latest 
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position 
enhancement is described by Goad et al. (2007, A&A, 476, 1401 
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is 
an extension of this method.


GRB_name: GRB090323A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9026
SUBJECT: GRB 090323: GROND Detection of the Afterglow and Photo-z
DATE:    09/03/24 05:06:41 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike (Clemson University), Robert Filgas (Tautenburg Obs.),
Thomas Kruehler, Jochen Greiner (MPE Garching), and Sheila McBreen
(University College Dublin) report on behalf of the GROND team:

We observed the field of GRB 090323 (Fermi trigger 259459364 / 090323002;
Ohno et al., GCN #9021) simultaneously in g'r'i'z'JHK with GROND (Greiner
et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La
Silla Observatory (Chile).

Observations started at 02:50 UT on March 24, 26 hours and 48 minutes time
after the GRB trigger, and are continuing. They were performed at an
average seeing of 1.3" and at an average airmass of 1.8.

We found a single point source within the 2.7" Swift-XRT error circle
reported by Kennea et al. (GCN #9024) at

RA (J2000) = 12h 42m 50.29s

DEC (J2000) = +17d 03' 11.6"

with an uncertainty of 0.5".

Based on the first 8 min of total exposures in g'r'i'z' J H Ks, we
estimate preliminary magnitudes (all in AB system) of

g' = 21.64 +/- 0.07 mag,

r' = 20.03 +/- 0.03 mag,

i' = 19.64 +/- 0.02 mag,

z' = 19.39 +/- 0.02 mag,

J = 19.24 +/- 0.02 mag,

H = 18.86 +/- 0.02 mag, and

K = 18.58 +/- 0.03 mag

Given magnitudes are calibrated against GROND zeropoints as well
as 2MASS field stars and are not corrected for the expected Galactic
foreground extinction corresponding to a reddening of E_(B-V)= 0.02 mag in
the direction of the burst (Schlegel et al. 1998).

Based on the given magnitudes, we find a photometric redshift of z = 4.0
+/- 0.3.


GRB_name: GRB090323A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9027
SUBJECT: GRB 090323: P60 Afterglow Confirmation
DATE:    09/03/24 05:55:03 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko and D. A. Perley (UC Berkeley) report on behalf of a larger
collaboration:

We have imaged the field of GRB090323 (Ohno et al., GCN 9021) with the
automated Palomar 60-inch telescope.  Observations were taken in the Sloan
r' and i' filters beginning at 2009 Mar 24 04:20 UT (~ 28.30 hr after the
burst).  Inside the XRT error circle (Kennea et al., GCN 9024) we find a
single source consistent with the position repored by Updike et al (GCN
9026).  At this epoch we measure magnitudes of r' = 20.5, i' = 20.0,
suggesting the source has faded since the observations reported therein
(referenced with respected to several nearby SDSS sources).  We therefore
confirm this object is the afterglow of GRB090323.


GRB_name: GRB090323A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9028
SUBJECT: GRB 090323 Gemini-South Redshift
DATE:    09/03/24 07:18:48 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

R. Chornock, D. A. Perley, S. B. Cenko, and J. S. Bloom (UC Berkeley) report on
behalf of a larger collaboration:

We performed spectroscopy on the afterglow of GRB 090323 (Ohno et al., GCN 9021;
Updike et al., GCN 9026; Cenko and Perley, GCN 9027) using Gemini-South (GMOS)
starting at 05:58 UT on 2009-03-24, approximately 30 hours after the trigger.
We conducted a series of four exposures of 600 seconds, two using the B600
grating centered at 6000 Angstroms and two with the R400 grating centered at
8000 Angstroms.

The first spectrum shows strong absorption blueward of 5580 Angs, which we
identify as the onset of the Lyman-alpha forest at z=3.6.  There are also narrow
absorptions with multiple components from C IV, O I, C II, and Si IV at a
consistent redshift of z=3.57.  Further analysis is ongoing.

We would like to thank the Gemini-S staff, in particular Etienne Artigau, Lucas
Fuhrman, and Benoit Neichel, for their support with these observations.


GRB_name: GRB090324A
Detection_method: superAGILE
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9029
SUBJECT: GRB 090324: SuperAGILE Localization of a Long GRB
DATE:    09/03/24 08:32:44 GMT
FROM:    Marco Feroci at IASF/INAF  <feroci@iasf-roma.inaf.it>

F. Lazzarotto, E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci, 
L. Pacciani, P. Soffitta, E. Costa, I. Lapshov, M. Rapisarda
(INAF/IASF Rome), A. Giuliani, A. Chen, S. Mereghetti, F. Perotti, 
P. Caraveo (INAF/IASF Milan), A. Pellizzoni, M. Pilia (INAF/OA Cagliari),
S. Vercellone (INAF/IASF Palermo), A. Bulgarelli, F. Gianotti,
M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi,
M. Galli, (INAF/IASF Bologna), M. Tavani, G. Pucella, F. D'Ammando, V.
Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini (INAF/IASF Rome), G. 
Barbiellini, F. Longo, E. Moretti (INFN Trieste), P. Picozza, A. Morselli 
(INFN Roma-2), M. Prest, E. Vallazza (Universita' dell'Insubria), P. 
Lipari, D. Zanello (INFN Roma-1), and  P. Giommi, C. Pittori, 
P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI),
on behalf of the AGILE Team, report:

"SuperAGILE detected a gamma ray burst on 24 March 2009, at 02:48:09 UT.
The event had a duration of about 30 s in the 20-60 keV energy range,
with an overall FRED-like time structure. Assuming a crab-like energy 
spectrum, the peak flux on 1-s timescale was 1.8E-07 erg/cm2/s.
The burst position was reconstructed  as (RA, Dec)
(257.178, -48.147) deg, which is:

RA(J2000)  = 17h 08m 42.73s
Dec(J2000) = -48d 08' 47.59"

with an uncertainty of 3' radius. The given uncertainty accounts
for both the statistical and systematic errors.

An analysis of the AGILE Gamma Ray Imager (GRID) data is in progress."

This message may be cited.


GRB_name: GRB090323A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9030
SUBJECT: Konus-Wind observation of GRB 090323
DATE:    09/03/24 12:25:07 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The long GRB 090323 (Fermi-GBM trigger 259459364 / 090323002) localized 
by Fermi-LAT (Ohno et al., GCN 9021; the LAT localization was confirmed 
by the IPN triangulation: Hurley et al., GCN 9023) triggered Konus-Wind 
at T0=174.632 s UT (00:02:54.632).

The burst light curve shows several pulses with a total duration of
~160 s, followed by a weak tail marginally seen up to ~T0+300 s in all 
energy bands.

As observed by Konus-Wind the burst
had a fluence of 2.02(-0.25, +0.28)x10^-4 erg/cm2,
and a 256-ms peak flux measured from T0+58.240 s
of 5.96(-1.06, +1.09)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+145.664 s) can be fitted (in the 20 keV - 10 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.96(-0.09, +0.12),
the high energy photon index beta = -2.09(-0.22, +0.16),
the peak energy Ep = 416(-73, +76) keV (chi2 = 104.0/89 dof).

All the quoted errors are at the 90% confidence level.

Assuming z = 3.6 (Chornock et al., GCN 9028)
and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27,
Omega_\Lambda = 0.73, the isotropic energy release E_iso ~5.6x10^54 erg,
the peak luminosity (L_iso)_max ~ 7.6x10^53 erg/s, and Ep_rest ~1900keV.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090323_T00174/


GRB_name: GRB090323A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9031
SUBJECT: GRB 090323: Swift-XRT refined analysis
DATE:    09/03/24 16:53:38 GMT
FROM:    Matteo Perri at ISAC/ASDC  <perri@asdc.asi.it>

M. Perri and G. Stratta (ASDC) report on behalf of the Swift-XRT team:

We have analysed the first 6 ks of Swift-XRT data of the Fermi GRB
090323 (Ohno et al., GCN Circ. 9021). The data, starting at 2009-03-23
19:27:51 UT and ending at 2009-03-24 09:47:02 UT, is all taken in
Photon Counting (PC) mode.

The X-ray source reported by Kennea et al. (GCN Circ. 9024) is found to
be fading and we thus confirm that it was the afterglow of GRB 090323.

In the time interval T+70 ks-T+121 ks the X-ray light-curve can be
modelled by a simple power law with a decay index alpha=2.1 (+0.9)(-0.7).

The X-ray spectrum is well fit by an absorbed power-law model with a
photon index of 2.2 (+/-0.4) and a column density consistent with the
Galactic one in the direction of the source (1.7e20 cm**-2, Kalberla
et al. 2005). The estimated 3-sigma (2-sigma) upper limit on the
intrinsic column density at z=3.6 (Chornock et al., GCN Circ. 9028) is
5.1e22cm**-2 (2.7e22cm**-2). All the quoted errors are at the 90%
confidence level.

Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10 keV XRT count rate of 5e-3 count/s at T+48hr, which
corresponds to an observed 0.3-10 keV flux of ~2e-13 erg/cm**2/s.

This circular is an official product of the Swift-XRT Team.


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9032
SUBJECT: GRB 090323: UVOT Detection of Afterglow
DATE:    09/03/24 19:40:58 GMT
FROM:    Erik Hoversten at Swift/Penn State  <hoversten@astro.psu.edu>

E. A. Hoversten (PSU) reports on behalf of the Swift UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 090323 70 ks after the Fermi LAT trigger (Ohno et al., GCN 9021).
The afterglow is detected in the UVOT white filter at:

     RA (J2000)  12:42:50.29
    Dec (J2000)  17:03:11.8

with an estimated uncertainty of 0.8 arcsec (radius, 90% confidence).
This position is consistent with the UVOT enhanced XRT position (Kennea
et al., GCN 9024) as well as the optical position determined by
GROND (Updike et al., GCN 9026)  The afterglow candidate does not
appear in the DSS images.  Photometry from the second set of Swift
observations may be indicative of fading, but is not deep enough to be
conclusive.

UVOT magnitudes and 3-sigma upper limits are reported in the following
table:

Filter   T_start   T_stop   Exp(s)  Mag (3-sigma upper limit)
-----------------------------------------------------
WHITE     70287     75931    1196   21.66 +/- 0.28
WHITE    115572    121460     601      > 21.60
V         70667     76062     517      > 19.88
U         69906     75078    1200      > 21.02

The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E(B-V) = 0.03 mag.
All photometry is on the UVOT photometric system described in Poole et al.
(2008, MNRAS, 383, 627).


GRB_name: GRB090323A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9033
SUBJECT: GRB 090323 TLS detection - still bright
DATE:    09/03/25 00:42:02 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, U. Laux and B. Stecklum (TLS Tautenburg) report:

We observed the afterglow (Updike et al., GCN 9026, Cenko et al. GCN 9027) 
of the intense Fermi GBM/LAT GRB 090323 (Ohno et al., GCN 9021) with the 
1.34m Schmidt telescope of the TLS Tautenburg observatory under inclement 
conditions (low transparency, passing clouds). We obtained 8 Rc frames of 
600 seconds exposure time each before clouds shut us down. The afterglow 
is faintly detected in each single image and clearly detected in the 
complete stack.

Assuming the star at RA = 12 42 39.3, Dec. = +17 05 05.7 to have Rc = 
17.15 (USNOR1=17.17, USNOR2=17.12), we measure the following afterglow 
magnitude:

days after trigger Rc dRc (statistical)

1.87751   20.88 0.04

This value is only slightly fainter than those reported ~18 hours earlier 
(Updike et al., GCN 9026, Cenko et al. GCN 9027), which may indicate the 
following:

- The afterglow is undergoing a plateau phase or possibly even a 
rebrightening (if it faded more inbetween).
- The magnitude of the comparison star is highly incorrect (e.g., variable 
star). But we also used several other comparison stars and find agreement 
within +/- 0.2 mags.

If the afterglow truly is this bright, this makes it one of the most 
luminous afterglows every detected, comparable or even exceeding the 
recent GRB 090313 (Perley et al., GCN 8985, de Ugarte Postigo et al., 
8992). The very low foreground extinction, excellent observability, low 
influence of moonlight combined with the extreme high energy properties 
(possible several ksec long tail emission in LAT, Ohno et al., GCN 9021, 
extremely high isotropic energy release, Golenetskii et al., GCN 9030) and 
the spectroscopic redshift (Chornock et al., GCN 9028) make this a GRB of 
special interest, and more observations, especially with medium-size 
telescopes, are encouraged. If weather permits, Tautenburg will continue 
observations.

This message may be cited.


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9034
SUBJECT: GRB 090323: Optical observation of xinglong TNT
DATE:    09/03/25 02:16:34 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

X.F. Wang, L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei,
j. Wang, J.S. Deng and J.Y. Hu on behalf of EAFON report:

We have observed GRB090323 (Ohno et al.GCN 9021;
Updike et al.GCN 9026; Cenko et al. GCN 9027) 
with Xinglong TNT telescope from Mar.24,14:51:14(UT), 
38.8 hr after the burst. After combined 10*600s R 
band images, the optical afterglow was detected about 
R=20.55 mag at the mean time of 1.651 days after the 
trigger, with the same calibration star 
(RA = 12 42 39.3, Dec. = +17 05 05.7, Rc=17.15) 
of kann et al., (GCN 9033).
 
Further observation is suggested,
for the late slowly decay of the optical afterglow.

This message may be cited.

For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/


GRB_name: GRB090323A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9035
SUBJECT: GRB 090323: Fermi GBM Spectral Analysis
DATE:    09/03/25 03:11:27 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the
Fermi GBM team:

"We have performed spectral analysis of the GBM data for GRB 090323
(GCN 9021). The analysis was restricted to the first ~70 seconds of
GRB emission, because after that time the Fermi Observatory executed
a maneuver following this bright GRB, which caused rapid, significant
changes in the source angles of the various detectors and in the
background behaviour.

The spectrum from T0-2.0 s to T0+71.7 s is best fit by a power-law
function with a high-energy exponential cutoff. The power-law index
is -0.89 +/- 0.03, and the cutoff energy, parameterized as Epeak, is
697 +/- 51 keV (chi squared 379.4 for 359 d.o.f.). At a redshift of
3.57 (GCN 9028), the Epeak in the GRB rest frame, Epeak_rest, is
3.19 +/- 0.23 MeV.

The event fluence (8-1000 keV) in this time interval is
(1.00 +/- 0.01)E-4 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+65.5 s in the 8-1000 keV band
is 12.3 +/- 0.4 ph/s/cm^2.

This time interval consists of two main emission peaks, from T0-2.0 s
to T0+33.8 s and from T0+33.8 s to T0+71.7 s. Both of these shorter
intervals are also best fit by a power-law function with a high-energy
exponential cutoff. For the first interval the power-law index is
-1.00 +/- 0.03, Epeak is 1173 +/- 175 keV, Epeak_rest is 5.36 +/- 0.80
MeV, and the fluence (8-1000 keV) is (3.68 +/- 0.06)E-5. For the second
interval the power-law index is -0.83 +/- 0.03, Epeak is 574 +/- 34 keV,
Epeak_rest is 2.62 +/- 0.16 MeV, and the fluence (8-1000 keV) is
(6.35 +/- 0.09)E-5.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9036
SUBJECT: GRB 090323: Lick observations
DATE:    09/03/25 10:43:03 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, C. R. Klein, A. N. Morgan, and E. Petigura (UC Berkeley) 
report:

We observed the afterglow of GRB 090323 (Ohno et al., GCN 9021; Updike 
et al., GCN 9026; Cenko et al., GCN 9027) with the Nickel 40in telescope 
at Lick Observatory starting at UT 06:45 on 2009-03-25 for a series of 
5- and 10- minute exposures totaling 55 minutes of integration time 
under photometric conditions.  The afterglow is detected in the stacked 
frame.  Using the same calibration star mentioned in Kann et al. (GCN 
9033), we calculate a magnitude of R = 21.3 +/- 0.2  at a mid-time of 
t=2.30 days after the trigger.  This suggests (within the uncertainty) 
that the afterglow has faded significantly since the observations of 
Kann et al. and Wang et al. (GCN 9034) ~12 hours prior and that the 
optical flattening phase may have ended.  Additional observations are 
planned.


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9037
SUBJECT: GRB 090323: RTT150 optical observations
DATE:    09/03/25 12:22:37 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>

R. Burenin, A. Tkachenko, M. Pavlinsky, R. Sunyaev (IKI),  
I. Khamitov, Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
I. Bikmaev, N. Sakhibullin (KSU/AST)

report:

The optical afterglow of GRB 090323 (Updike et al., GCN 9026, Cenko et
al., GCN 9027) was observed with Russian-Turkish 1.5-m telescope
(RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey). We obtained
6x600s exposures in sdss-r filter, centered at March 25, 01:30 UT,
i.e. 2.059 days after the burst.

The afterglow is detected in all frames. Using the same calibration star
as it was used by Kann et al. (GCN 9033), we esimate the magnitude of
the OT as R=20.85+-0.04. During our observations we also marginally
detected gradual decline of the afterglow brightness at a rate of
approximately 0.3 mag/hour, which is steeper than that assumed by the
comparison with the data obtained by Perley et al. (GCN 9036).

Our light curve and finding chart can be found at:

http://hea.iki.rssi.ru/grb/090323/indexeng.html


GRB_name: GRB090320B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9038
SUBJECT: GRB 090320B: MASTER-Net prompt optical observations
DATE:    09/03/25 16:39:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parhomenko,
   Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinski, I.Zalognikh, T.Kopytova
Ural State University, Kourovka


S.Yazev, K.Ivanov
Irkutsk State University


There are 6 MASTER Very Wide Field cameras located at Kislovodsk and 
Irkutsk with common FOW = 6000 square degrees 
(http://observ.pereplet.ru/).

One of the four  MASTER Very Wide Field Cameras located at Kislovodsk
(D=50 mm, 4x1000 square degrees, 11 Mpx) has observed  ~80% 1-sigma Fermi
error box  (P. N. Bhat, GCN 9020) with 1s exposure
during  all night: befoure, during and after GRB Time
without time gap between images.

Our unfiltered images are calibrated relative to Tycho stars (V).
The magnitude limit of the each emage is  ~9.0 m at the edge of FOW (some 
ising was attend at this night).

We do not detect OT inside 80% part of the error box.

  T-T_trigger            m_lim (S/N=3)         Exposure         Coadd

-10s... 0... 60 s          9.0                   1 s             no
-1min...0...+1 min        10.5                  10 s             10
-1min...0...+1 min        11.0                  60 s             60

We  conclude (in the case that GRB inside our FOW ):

1). the optical fluence during the short 58 s GRBurst is limited by

                        ~<=  1.5 x 10E-8 erg/cm_2

excluding possible  host galaxy absorbtion.

The event fluence (8-1000 keV) in this time interval is
(1.1 +/- 0.3)E-06 erg/cm^2 (P. N. Bhat, GCN 9020).

So:

2).  Optical-Fluence/Gamma-Fluence(8-1000 keV) ~ < 1/70

The same ratio for long GRB080319B is

Optical-Fluence/Gamma-Fluence(8 - 1000 keV) ~ 1/140

(Naked Eye GRB, Racusin, Karpov et al., Nature, vol.455, 183, 2008).


The film of our observations (from -10 s before to 60 s after GRB time) 
is available at

http://observ.pereplet.ru/images/GRB090320B/GRB090320b_10sec_bin.gif

Black circle is the 1-sigma (9.5 degrees, P. N. Bhat, GCN 9020)
error box.

The film of added images (60s effective exposition) our observations (from 
-60s before to 60 s after GRB time)is available at
http://observ.pereplet.ru/images/GRB090320B/GRB090320B_60sec.gif

The reduction is continued.

The message may be cited.

mailto: lipunov@sai.msu.ru




  T-T_trigger            m_lim (S/N=3)         Exposure         Coadd

-255s... 0... 255 s       11.8                  5s              yes 
-2min...0...+2 min        12.7                 2x30s             12
-2min...0...+2 min        13.0                 2x60s             24

The optical fluence during the 40s-GRBurst is limited by

     <= 1.6x10_-8 erg/cm_2


including 2.8 magnitude  absorbtion (Ukwatta et al., Circ 8462).
The  BAT-fluence is aboute 2.3x10_-6 erg/cm_2 (15-150 keV) (Fenimore et al., 
GCN 8468).

So:

Optical Fluence/Gamma-Fluence(15-150keV) ~ < 1/140

Same ratio for GRB080319B is ~ 1/25 (Naked Eye GRB) in 15-150 keV (Racusin, 
Karpov et al., Nature, vol.455, 183, 2008).


Scientific Master Team Report   are available at
http://observ.pereplet.ru/images/GRB081102/grb_film.html

Note: the GRB was at the edge of the FOW in both cameras.
The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090323A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9039
SUBJECT: GRB 090323: Faulkes Telescope South Observations
DATE:    09/03/26 10:11:36 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), I. A. Steele, A. Melandri, D. Bersier 
(Liverpool JMU),
A. Gomboc (U. Ljubljana), S. Kobayashi, C.J. Mottram, C.G.  Mundell,
R.J. Smith (Liverpool JMU), P. O'Brien, N. Bannister, N. Tanvir (U. 
Leicester)
on behalf of a large collaboration report:

The 2-m Faulkes Telescope South (Siding Spring, Australia) began observing
the afterglow (Updike et al., GCN Circ. 9026; Cenko et al., GCN Circ. 9027)
of the Fermi GBM/LAT GRB 090323 (Ohno et al., GCN Circ. 9021; van der Horst
et al., GCN Circ. 9035) on March 25, 11:50:55 UT, i.e. at 2.49 days post 
burst.

Observations were carried out in filters R and i. The afterglow is
clearly detected in both filters with the following magnitudes:

Filter  Tmid(days)    Exposure(s)    Mag
-------------------------------------------------
   i       2.50         6x300        21.3 +/- 0.2
   R       2.53         6x300        21.7 +/- 0.1
-------------------------------------------------

Magnitudes are calibrated with respect to nearby SDSS stars.
Comparing with previous reports (Kann et al., GCN Circ. 9033; Wang et al.,
GCN Circ. 9034; Perley et al., GCN Circ. 9036; Burenin et al., GCN Circ. 
9037)
we confirm the steepening of the decay.


GRB_name: GRB090327A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9040
SUBJECT: GRB 090327: Fermi GBM detection
DATE:    09/03/27 16:32:30 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 09:41:41.51 UT on 27 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090327 (trigger 259839703 / 090327404).
The on-ground calculated location, using the GBM trigger 
data, is RA = 29.5, DEC = -41.6 (J2000 degrees,
equivalent to 01h 58m, -41d 36'), with an uncertainty 
of  3.4 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 66 degrees.

The GBM light curve consists of single peak
with a duration (T90) of about 24 s (8-1000 keV). 
The time-averaged spectrum from T0 to T0+16.384 s is  
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.50 +/- 0.12 and
the cutoff energy, parameterized as Epeak, is 96.4 +/- 5.1 keV
(chi squared 550 for 475 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(3.0 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+9.216 s in the 8-1000 keV band 
is 3.5 +/- 0.7  ph/s/cm^2.

A Band function fits the spectrum equally well (chi squared 549 
for 474 d.o.f.) with Epeak= 89.7 +/- 7.0  keV, 
alpha = -0.39 +/- 0.16 and beta = -2.90 +/- 0.45. 

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090323A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9041
SUBJECT: GRB 090323: TLS detection at 5 days, no break
DATE:    09/03/28 04:23:25 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, U. Laux and B. Stecklum (TLS Tautenburg) report:

We observed the afterglow (Updike et al., GCN 9026, Cenko et al. GCN 9027) 
of the intense Fermi GBM/LAT GRB 090323 (Ohno et al., GCN 9021) with the 
1.34m Schmidt telescope of the TLS Tautenburg observatory under decent 
conditions (low transparency). We obtained 11 Rc frames of 600 seconds 
exposure time each before dawn shut us down. The afterglow is faintly 
detected in some single images and well-detected in the 
complete stack.

Using the same comparison star as Kann et al. (GCN 9033), we measure the 
following afterglow magnitude:

days after trigger Rc dRc (statistical)

5.10418   22.67 0.20

Using other published data (Updike et al., GCN 9026, Wang et al., GCN 
9034, Perley et al. GCN 9036, Guidorzi et al., GCN 9039) as well as 
additional TLS data from the first observation run, we find that all data 
agree decently well with a single power law decay with a slope alpha ~ 
1.8. Therefore, there does not seem to be a plateau phase, but there is 
also no sign of a break yet. The relatively steep decay makes it unclear 
if this is a steep pre-break decay slope or a shallow post-break decay 
slope. In the latter case, it will be possible to track the afterglow for 
a very long time. Further deep, high S/N observations with larger 
telescopes are advised.

This message may be cited.


GRB_name: GRB090323A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9042
SUBJECT: GRB 090323: Additional Lick observations
DATE:    09/03/28 06:28:09 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley (UC Berkeley) reports:

On the night of 2009-03-27 (UT) I returned to the location of the 
afterglow of GRB 090323 (Updike et al., GCN 9026; Cenko et al., GCN 
9027) with the Nickel 40-inch telescope at Lick Observatory and acquired 
an additional series of 900s R-band exposures between 05:12 and 12:26 UT 
totaling 260 minutes of integration time.

While not clearly visible in individual exposures, the afterglow is 
detected in stacked frames.  Using the calibration star of Kann et al. 
(GCN 9033), I measure a magnitude of R = 22.63 +/- 0.18 at an 
observation mid-point of t = 4.36 days in a stack of all observations 
throughout the night, consistent with the absence of a break in the 
light curve reported by Kann et al. (GCN 9041).

I thank Mo Ganeshalingam for the exchange of observing time.


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9043
SUBJECT: GRB 090323: Radio afterglow detection
DATE:    09/03/28 22:57:52 GMT
FROM:    Dale A. Frail at NRAO  <dfrail@nrao.edu>

  F. Harrison (Caltech), B. Cenko (UC Berkeley), D. A. Frail (NRAO),
P. Chandra (RMC), and S. Kulkarni (Caltech) report:

"We observed the field centered at the optical afterglow (GCN
Circ. 9026) of the Fermi GBM/LAT GRB 090323 (GCN Circ. 9021, GCN
Circ. 9035) on March 27.38 UT using the Very Large Array (VLA) at a
frequency of 8.46 GHz. We detect an unresolved radio source at the
GRB afterglow position with the flux density of 225+/-35 uJy at
a (J2000) position of:

RA  = 12h 42m 50.292s
DEC = +17d 03' 11.90"

with an uncertainty of 0.05" Further observations are planned.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090328A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9044
SUBJECT: Fermi LAT and GBM detections of GRB090328
DATE:    09/03/28 23:18:16 GMT
FROM:    Julie McEnery at UMBC/GSFC  <mcenery@milkyway.gsfc.nasa.gov>

Julie McEnery (NASA/GSFC), Sara Cutini (ASDC), Masanori Ohno (ISAS/JAXA)  and Elmar Koerding (AIM/Saclay) report on behalf of the Fermi LAT  collaboration and Valerie Connaughton (UAH) reports on behalf of the 
Fermi GBM collaboration

At 09:36.46 UT on 28 March 2009, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 090328 (trigger 259925808 / GRB090328401). The  GBM lightcurve shows a multi-peaked event, with the brightest set of peaks occurring within 50 sec and a further peak at 60 sec tailing off  beyond 100 sec post-trigger. The burst is detected at least to 1 MeV.

The Fermi Large Area Telescope (LAT) has significantly detected this GRB. Emission was observed in the LAT up to a few GeV with a detection  significance of more than 5 sigma.

The current best LAT on-ground localization is found to be (RA,Dec=90.87, -41.95) with a 68% containment radius of 0.11 deg, and a systematic error less than 0.1 deg. The GBM on-ground localization is consistent with this LAT localization within statistical and systematic uncertainties.

We further report that the Fermi Observatory executed a maneuver following this trigger and tracked the burst location for the next 5 hours, subject to Earth-angle constraints.

Swift TOO observations have been requested at the LAT measured position.

Further analysis is ongoing.

The points of contact for this burst are Julie McEnery (LAT, julie.mcenery@nasa.gov) and Valerie Connaughton (GBM, valerie@nasa.gov).

The Fermi LAT is a pair conversion telescope designed to cover the  energy band from 20 MeV to greater than 300 GeV. It is the product of an  international collaboration between NASA and DOE in the U.S. and many  scientific institutions across France, Italy, Japan and Sweden.

This message can be cited.


GRB_name: GRB090328A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9045
SUBJECT: GRB 090328: Possible Swift/XRT detection
DATE:    09/03/29 04:27:22 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>

J. Kennea (PSU) reports on behalf of the Swift/XRT Team:

Swift began a TOO observation observation of the LAT error circle of GRB 
090328 (McEnery et al, GCN #9044) at 01:26UT March 29th, 2009. Preliminary 
analysis of the downlinked XRT data finds an uncatalogued X-ray source 
approximately 10 arcminutes from the centre of the LAT error circle, at 
the following location: RA, Dec = 90.66485, -41.88421 which is equivalent 
to:

RA(J2000) =  06h 02m 39.6s
Dec(J2000)= -41d 53m 03.2s

with an estimated uncertainty of 6 arcseconds radius (90% confidence). We 
cannot confirm at this time if the afterglow candidate is fading.


GRB_name: GRB090328A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9046
SUBJECT: GRB 090328: Updated position/optical afterglow candidate
DATE:    09/03/29 05:46:10 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>

J. Kennea (PSU), P. Evans and M. Goad (U Leicester) report on behalf of 
the Swift/XRT Team:

Further analysis of the candidate afterglow of GRB 090328 has been 
performed utilizing downlinked Swift XRT and UVOT data. Using 1329 s of 
XRT Photon Counting mode data and 2 UVOT images, we find an 
astrometrically corrected X-ray position (using the XRT-UVOT alignment and 
matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 90.66494, 
-41.88265 which is equivalent to:

RA (J2000):  06 02 39.58
Dec (J2000): -41 52 57.5

with an uncertainty of 2.0 arcsec (radius, 90% confidence). Position 
enhancement is described by Goad et al. (2007, A&A, 476, 1401 
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is 
an extension of this method.

Swift/UVOT detects a point source at a location consistant with the 
XRT error circle, detected in the U and White filters. A catalogue search 
does not reveal any known source at the location of this source. We 
tentatively suggest that this UVOT source may be the optical afterglow of 
GRB 090328, although this cannot be confirmed until either the optical or 
X-ray afterglow candidates are seen to fade.


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9047
SUBJECT: GRB 090323: WSRT Radio Detection
DATE:    09/03/29 11:01:03 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of a large
collaboration:

"We observed the position of the GRB 090323 afterglow at 4.9 GHz with the
Westerbork Synthesis Radio Telescope at March 27 17.92 UT to March 28
5.91 UT, i.e. 4.74 - 5.24 days after the burst (GCN 8980).
We detect a radio source with a flux density of 105 +/- 24 microJy
at the position of the optical counterpart (GCN 9021).

We would like to thank the WSRT staff for scheduling and obtaining these
observations."


GRB_name: GRB090328A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9048
SUBJECT: GRB 090328: Swift UVOT observations
DATE:    09/03/29 15:11:20 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began observing the field of GRB 090328 16 hrs
after the Fermi LAT trigger (McEnery et al., GCN 9044). We detect
a candidate optical afterglow in the u and white filters at:

RA(J2000)  = 06:02:39.67
DEC(J2000) = -41:52:54.5

with an estimated uncertainty of 0.6 arcsec (radius, 90% confidence).
At the moment we are unable to tell if the source is fading, further
observations have been performed, but due to a data gap, the data
is currently unavaliable.

Preliminary magnitudes for the white and u filters are:

Filter    T_mid (hrs)  Exposure(s)       Mag  Err
------------------------------------------------------------
u         16.0         793           19.04 +/- 0.13
white     16.1         173           19.56 +/- 0.14

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.06 mag (Schlegel et al.,
1998, ApJS, 500, 525).  The photometry is on the UVOT flight system
described in Poole et al. (2008, MNRAS, 383,627).


GRB_name: GRB090328A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9049
SUBJECT: GRB 090328:  IPN Triangulation
DATE:    09/03/29 18:06:02 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T.Cline on behalf of the Konus-Wind team,

A. von Kienlin, G. Lichti, A. Rau, and K. Hurley on behalf of the
INTEGRAL SPI-ACS GRB team, and

V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM
team, report:

Konus-Wind and INTEGRAL (SPI-ACS) have so far observed the long bright
GRB 090328 (McEnery et al. GCN 9044). We have triangulated this
burst to a Konus-SPI-ACS annulus centered at RA(2000),
Dec(2000) =26.911, +1.465, whose radius is 72.339 +/-  0.671 degrees (3 
sigma).
This annulus intersects the GBM localization, and the LAT localization
lies 0.357 degrees from the center line of this annulus. A map is
posted at http://www.ioffe.ru/LEA/GRBs/GRB090328_T34609/IPN/
showing the GBM contours (statistical) and best-fit position (diamond),
the IPN annulus (solid line), and the LAT best-fit position (diamond)
and error circle (68% CL, statistical).

This map will also be posted at http://ssl.berkeley.edu/ipn3/090328 .

The IPN localization may be improved.


GRB_name: GRB090328A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9050
SUBJECT: Konus-Wind observation of GRB 090328
DATE:    09/03/29 18:18:18 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The long bright GRB 090328 (Fermi-GBM trigger trigger 259925808 / 
GRB090328401) localized by Fermi-LAT (McEnery et al., GCN 9044; the LAT 
localization was confirmed by the IPN triangulation: Golenetskii et al., 
GCN 9049) triggered Konus-Wind at T0=34609.486 s UT (09:36:49.486).

The burst light curve shows a multipeaked structure with a duration of
~80 s. There is a hint of an extended soft emission.

As observed by Konus-Wind the burst
had a fluence of 9.25(-1.98, +1.63)x10^-5 erg/cm2,
and a 64-ms peak flux measured from T0+20.064 s
of 1.22(-0.26, +0.25)x10^-5 erg/cm2/s
(both in the 20 keV - 8 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+72.960 s) is well fitted (in the 20 keV - 8 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -1.04(-0.10, +0.11),
the high energy photon index beta = -2.05(-0.90, +0.22),
the peak energy Ep = 592(-141, +237) keV (chi2 = 78.4/81 dof).


The spectrum of the most intense part
(from T0 to T0+23.808 s) is well fitted (in the 20 keV - 8 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.94 +/- 0.08,
the high energy photon index beta = -2.07(-0.36, +0.16),
the peak energy Ep = 600(-100, +147) keV (chi2 = 81.1/81 dof).
The fluence of this part is 7.48(-0.93, +0.83)x10^-5 erg/cm2 (in the 20 
keV - 8 MeV energy range).

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090328_T34609/


GRB_name: GRB090323A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9051
SUBJECT: GRB090323: Optical observations from NOT
DATE:    09/03/29 20:21:03 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (ESO), D. Xu,  D. Malesani, J. Hjorth,
J.P.U. Fynbo (DARK/NBI), P. Jakobsson (Univ. of Iceland),
A. Adamo, G. Micheva (Stockholm Univ.) on behalf  of a larger collaboration
report:

We have observed the field of GRB 090323 (Ohno et al. GCN 9021)
with the 2.5m NOT telescope (+ALFOSC) at Roque de los Muchachos
Observatory (Spain). The mean epoch of our observations is March
29.323 UT (6.327 days after the burst). The afterglow (Kennea et
al. GCN 9024, Updike et al. GCN 9026) is clearly detected in the
6x300s combined exposure with R=22.80+/-0.06.  As photometric
reference we used the object indicated by Kann et al. (GCN 9033).
Our measurement is consistent with the absence of a light curve
steepening, as noted one day earlier by Kann et al. (GCN 9041).
A lightcurve composed of GCN data together with our observation
shows a possible flattening during the last 3 days.

Further observations are foreseen.

[GCN OPS NOTE(29mar09): Per author's request, GM was added 
to the author list.]


GRB_name: GRB090328A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9052
SUBJECT: GRB 090328: Swift XRT refined analysis
DATE:    09/03/29 20:39:01 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

A. Rowlinson and K. Page (U. Leicester) report on behalf of the
Swift/XRT Team:

We have analysed 3.4 ks of XRT data for the Fermi GBM and LAT detected
GRB 090328 (McEnery et al. GCN Circ. 9044, Kennea et al. GCN Circ.
9045), from 57.1 ks to 94.3 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode.

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.60 (+/-0.28).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.9 (+0.3, -0.4). The
best-fitting absorption column is 1.9 (+1.4, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 5.0 x 10^20 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 4.9 x 10^-11 (6.6 x 10^-11) erg
cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
2.60, the count rate at T+48 hours will be 0.004 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.96 x
10^-13(2.64 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00031387.

This circular is an official product of the Swift-XRT team


GRB_name: GRB090328A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9053
SUBJECT: GRB 090328: Gemini South Redshift
DATE:    09/03/30 02:50:53 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko, J. S. Bloom, A. N. Morgan, and D. A. Perley (UC Berkeley)
report on behalf of a larger collaboration:

We have obtained optical spectra of the candidate UVOT afterglow (GCN
9046, 9048) of the Fermi GRB090328 (GCN 9044) with the Gemini Multi-Object
Spectrograph mounted on the Gemini South Telescope.  Observations began at
00:05 UT on 2009 March 29.

Our first 1500 second spectrum uses the R400 grating and covers the
approximate wavelength range from 4000-8000 A.  We find a single bright
emission line at observed wavelength ~ 6470 A that we identify as
[OII] 3727 at z = 0.736, along with an absorption doublet consistent with
Mg II 2796/2803 at the same redshift.  We therefore suggest that
this is the redshift of GRB090328.  Further observations are in progress.

We wish to thank the entire staff at Gemini observatory, in particular M.
Edwards and J. Blakeslee, for the prompt execution of our observations.


GRB_name: GRB090328A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9054
SUBJECT: GRB 090328: GROND Detection of the Optical/NIR Afterglow
DATE:    09/03/30 03:36:16 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria Updike (Clemson University), Sylvio Klose (Tautenburg Obs.),
Christian Clemens and Jochen Greiner (MPE Garching) report on behalf of
the GROND team:

We observed the field of GRB 090328 (Fermi trigger 259925808; McEnergy et
al., GCN 9044) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla
Observatory (Chile).

Observations started at 23:24 UT on date, about 1.6 days after the GRB
trigger, and are continuing. They were performed at an average seeing of
1.8" and at an average airmass of 1.06.

We detect the afterglow reported by Kennea et al. (GCN 9045) in all bands.

Based on the first 8 min of total exposures in g'r'i'z' JHK, we estimate
preliminary magnitudes (all in AB system) of

g' = 20.97 +/- 0.05 mag,

r' = 20.23 +/- 0.03 mag,

i' = 19.89 +/- 0.04 mag,

z' = 19.54 +/- 0.03 mag,

J = 19.54 +/- 0.06 mag,

H = 19.02 +/- 0.06 mag and

K = 18.52 +/- 0.08 mag

Given magnitudes are calibrated against USNO as well as 2MASS field stars
and are not corrected for the expected Galactic foreground extinction
corresponding to a reddening of E_(B-V) = 0.06 mag in the direction of the
burst (Schlegel et al. 1998).


GRB_name: GRB090330A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9055
SUBJECT: GRB 090330: Fermi GBM detection
DATE:    09/03/30 15:59:50 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 06:42:22.10 UT on 30 March 2009, the Fermi Gamma-Ray Burst Monitor 
triggered and located GRB 090330 (trigger 260088144 / 090330279).
The on-ground calculated location, using the GBM trigger 
data, is RA = 159.2, DEC = -7.7 (J2000 degrees, 
equivalent to 10h 37m, -07d 42'), with an uncertainty 
of 2.1 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 50 degrees.

The GBM light curve consists of a slowly rising pulse 
with a duration (T90) of about 80 s (8-1000 keV). 
The time-averaged spectrum from T0-2.048 s to T0+24.576 s is 
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.01 +/- 0.04 and 
the cutoff energy, parameterized as Epeak, is 261 +/- 18 keV 
(chi squared 606 for 609 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(1.14 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+12.288 s in the 8-1000 keV band 
is 6.8 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well 
(chi squared 605 for 608 d.o.f.) with Epeak= 246 +/- 25 keV, 
alpha = -0.99 +/- 0.05 and beta = -2.68 +/- 0.55. 

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090328B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9056
SUBJECT: GRB 090328B: Fermi GBM Detection
DATE:    09/03/30 18:06:00 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein@msfc.nasa.gov>

A. Goldstein (UAH) reports on behalf of the Fermi GBM Team: 

"At 17:07:04.94 UT on 28 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090328B (trigger 259952826 / 090328713).
The Fermi Observatory executed a maneuver following this trigger and 
tracked the burst location for the next 5 hours, subject to 
Earth-angle constraints.

The on-ground calculated location, using the GBM trigger 
data, is RA = 155.72, DEC = +33.40 (J2000 degrees, 
equivalent to 10h 23m, 33d 24'), with an uncertainty 
of 7.94 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 74 degrees.

The GBM light curve consists of a single bright peak
with a duration (T90) of about 0.32 s (8-1000 keV). 
The time-averaged spectrum from T0-0.13 s to T0+0.13 s is 
well fit by a Band function with Epeak = 1967.0 +/- 701.0 keV, 
alpha = -0.92 +/- 0.06, and beta = -2.48 +/- 0.66
(chi squared 452.6 for 482 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(9.61 +/- 0.31)E-07 erg/cm^2. The 0.064-sec peak photon flux measured 
starting from T0+0.0 s in the 8-1000 keV band 
is 29.83 +/- 2.38 ph/s/cm^2. 

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090328A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9057
SUBJECT: GRB 090328: Fermi GBM Spectral Analysis
DATE:    09/03/30 20:10:37 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne Rau (MPE), Valerie Connaughton (UAH) and Michael Briggs (UAH) 
report on behalf of the Fermi GBM team:

"We have performed spectral analysis of the GBM data for GRB 090328 (GCN 
9044).

The spectrum from T0+3.1s to T0+29.7s is best fit by a Band function 
with indices alpha=-0.93 +/- 0.02 and beta=-2.2 +/- 0.1, and peak energy 
of Epeak=653 +/- 45 keV (chi squared 365 for 311 d.o.f.). At a redshift 
of 0.736 (GCN 9053), the Epeak in the GRB rest frame, Epeak_rest, is 
1133 +/- 0.078 MeV.

The event fluence in this time interval is (8.09 +/- 0.10)E-5 erg/cm^2 
in the 8-1000 keV band and (9.5 +/- 1.0)E-5 erg/cm^2 in the 8keV-40MeV 
band. Using standard cosmology (Omega_matter = 0.27, Omega_lambda = 
0.73, H0=71) the isotropic equivalent energy in the 8keV-40MeV band is 
E_iso = (2.3 +/- 0.2)E+53 ergs. The 1-sec peak photon flux measured 
starting from T0+23.5 s in the 8-1000 keV band is 18.5 +/- 0.5 ph/s/cm^2.

This time interval consists of three main emission peaks, from T0+3.1s 
to T0+8.2s, from T0+13.3s to T0+19.5s, and from T0+23.6 to T0+25.6s. All 
of these shorter intervals are also best fit by a Band function. For the 
first interval the power-law indices are alpha=-0.79 +/- 0.04 and 
beta=-2.3 +/- 0.2, Epeak is 648 +/- 68 keV, Epeak_rest is 1125 +/- 118 
keV, and the fluence (8-1000 keV) is (3.80 +/- 0.08)E-06. For the second 
interval the power-law indices are alpha=-0.86 +/- 0.03, beta=-2.3 +/- 
0.2, Epeak is 676 +/- 62 keV, Epeak_rest is 1174 +/- 108 keV, and the 
fluence (8-1000 keV) is (4.35 +/- 0.07)E-6. For the third interval the 
power-law indices are alpha=-0.94 +/- 0.05, beta=-2.4 +/- 0.3, Epeak is 
481 +/- 60 keV, Epeak_rest is 835 +/- 104 keV, and the fluence (8-1000 
keV) is (4.3 +/- 0.1)E-6.

The spectral analysis results presented above are preliminary; final 
results will be published in the GBM GRB Catalog."


GRB_name: GRB090328A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9058
SUBJECT: GRB 090328: BOOTES-3 optical observations
DATE:    09/03/30 23:58:43 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

Bill Allen (Vintage Lane Obs., Blenheim, New Zealand), Phil Yock (Auckland
Univ., NZ), A. de Ugarte Postigo (ESO Santiago), Ian Bond (Massey Univ., NZ),
John Hearnshaw (Univ. of Canterbury, NZ), Grant Christie (Stardome Obs., NZ),
Petr Kubnek (GACE, Univ. of Valencia), S. Castillo (Univ. de Mlaga),
J. M. Castro Cern (ESAC Madrid), T. Mateo Sanguino (Univ. de Huelva),
D. Prez-Ramrez (Univ. de Jan), M. Cervio, A. Claret, J. M. Garca Pelayo,
J.  Gorosabel, S. Guziy, M. Jelnek, S. Martn Ruiz and A. J. Castro-Tirado
(IAA-CSIC Granada), report:

"Following the detection by Fermi LAT and GBM of GRB 090328 (McEnery
et al. GCNC 9044), follow-up observations were performed by the 0.6-m
Yock-Allen robotic telescope at the new BOOTES-3 astronomical station in
Blenheim (New Zealand). A co-added 1500s unfiltered image, obtained on
29 Mar (10:12-10:41 UT, i.e. 24.8 hr after the onset of the event) shows 
a rather bright optical afterglow at the UVOT position reported by Kennea et al. 
(GCNC 9046). We measure R~19.7+/-0.3 (clear filter), calibrated against USNO-B1.0
stars.  Additional observations are encouraged."

This message can be quoted.

[GCN OPS NOTE(31mar09):  Per author's request, the numerical values of the times
(which were local time) were converted to true UT time values; the "36.8 hrs"
was changed to "24.8"; and Cervino was added to the author list.]


GRB_name: GRB090326A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9059
SUBJECT: GRB 090326: Fermi GBM detection
DATE:    09/03/31 04:24:09 GMT
FROM:    Michael S. Briggs at UAH and MSFC  <michael.briggs@nasa.gov>

Michael S. Briggs (UAH)
reports on behalf of the Fermi GBM Team:

"At 15:10:49.48 UT on 26 March 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090326 (trigger 259773051 / 090326633).

The on-ground calculated location, using the GBM trigger
data, is RA = 259.6, DEC = -11.6 (J2000 degrees,
equivalent to 17 h 18 m, -11 d 36'), with an uncertainty
of 1.8 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 103 degrees.

The GBM light curve shows two peaks
with a duration (T90) of about 11.2 s (8-1000 keV).
The time-averaged spectrum from T0-3.072 s to T0+10.240 s is
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.86 +/- 0.22 and
the cutoff energy, parameterized as Epeak, is 75. +/- 8. keV.
The fluence in this time interval is (8.6 +/- 1.8)E-07 erg/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090328A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9060
SUBJECT: GRB 090328: Radio afterglow detection
DATE:    09/03/31 13:04:13 GMT
FROM:    Dale A. Frail at NRAO  <dfrail@nrao.edu>

D. A. Frail (NRAO), P. Chandra (RMC), and B. Cenko (UC Berkeley)
report on behalf of a larger collaboration:

"We observed a field toward the optical afterglow (GCN Circ. 9046, GCN
Circ. 9048) of the Fermi GBM/LAT GRB 090328 (GCN Circ. 9044, GCN
Circ. 9057) on March 30.99 UT using the Very Large Array (VLA) at a
frequency of 8.46 GHz. We detect an unresolved radio source at the GRB
afterglow position with a flux density of 337+/-60 uJy at a (J2000)
position of:

RA  =  06h 02m 39.67s
DEC = -41d 52' 53.8"

with a conservative error of 0.25" The source was not detected (<180
uJy) in observations taken 24 hours earlier. Further observations are
planned.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090324A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9061
SUBJECT: GRB 090324: Suzaku WAM observation of the prompt emission
DATE:    09/03/31 17:50:35 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka@phys.aoyama.ac.jp>

M. Suzuki, M. Ohno, M. Kokubun, T. Takahashi (ISAS/JAXA),
N. Kodaka, W. Iwakiri, M. Tashiro, Y. Terada, Y. Urata, A. Endo,
K. Onda, K. Morigami, T. Sugasahara (Saitama U.), T. Enoto, 
K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka
(Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), T. Uehara, 
T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.), 
E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono, 
H. Hayashi (Univ. of Miyazaki), S. Hong (Nihon U.), N. Vasquez 
(Tokyo Tech.), on behalf of the Suzaku WAM team, report: 

The long GRB 090324 localized by SuperAGILE (Feroci et al., GCN 9029) 
triggered the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 02:47:17.604 UT (=T0).
The observed light curve shows a double-peaked structure starting at
T0-1s, with a duration (T90) of about 70 seconds. We note that the
second peak starting around T0+50s corresponds to the FRED-like pulse
observed by SuperAGILE.
The fluence in 100 - 1000 keV was 8.8(-2.4, +1.0)x10^-6 erg/cm^2. The
1-s peak flux measured from T0+59s was 0.99(-0.12, +0.05) photons/cm^2/s 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s
to T0+89s is well fitted by a single power-law with a photon index
of  2.0(-0.2, +0.3) (chi^2/d.o.f = 10.1/13).
From a time resolved analysis of the first peak (T0-1s to T0+49s) and
the second peak (T0+49s to T0+89s), we found that both spectra 
 were fitted by single power-law models.
There is hard to soft spectral evolution from the first peak to the
second peak; corresponding photon indices of the first and the second
intervals are 1.7+/-0.3 and 2.4(-0.3, +0.4) respectively.

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:
 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090401A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9062
SUBJECT: GRB 090401: Swift detection of a burst
DATE:    09/04/01 00:23:21 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

P. Schady (MSSL-UCL), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/USRA/GSFC), H. A. Krimm (CRESST/GSFC/USRA),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC),
B. A. Rowlinson (U Leicester) and L. Vetere (PSU) report on behalf of
the Swift Team:

At 00:00:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090401 (trigger=348128).  The BAT on-board calculated 
location is RA, Dec 350.909, +29.767 which is 
   RA(J2000)  =  23h 23m 38s
   Dec(J2000) = +29d 46' 00"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a small peak at
~T+30 sec and then two large peaks at ~T+100 and ~T+120 sec. 
The peak count rate was ~4000 counts/sec (15-350 keV), at ~120 sec
after the trigger. 

Due to an observing constraint, Swift cannot slew to
the BAT position. It will not be possible to observe
until 2nd May due to a sun constraint. There will thus 
be no XRT or UVOT data for this trigger. 

Burst Advocate for this burst is P. Schady (ps AT mssl.ucl.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9063
SUBJECT: GRB 090323: Further TLS detections - a break?
DATE:    09/04/01 02:22:46 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, U. Laux, F. Ludwig and B. Stecklum (TLS Tautenburg) report:

We observed the afterglow (Updike et al., GCN 9026, Cenko et al. GCN 9027) 
of the intense Fermi GBM/LAT GRB 090323 (Ohno et al., GCN 9021) with the 
1.34m Schmidt telescope of the TLS Tautenburg observatory at several 
epochs.

At ~6 days after the GRB, conditions were bad (low transparency and 
passing clouds). We obtained 21 Rc frames of 600 seconds exposure time 
each. Only four of these are usable. The afterglow is faintly detected in 
the complete stack.

Using the same comparison star as Kann et al. (GCN 9033), we measure the 
following afterglow magnitude:

days after trigger Exposure Rc dRc (statistical)

5.89127   4 x 600  23.13 0.50

At ~7 days after the GRB, conditions were very bad (almost complete 
overcast). We obtained 1 Rc frames of 600 seconds exposure time which had 
good quality. The afterglow is not detected.

days after trigger Exposure Rc

6.99881   1 x 600  > 22.50

This limit is not constraining.

At ~9 days after the GRB, conditions were very good (good transparency, 
good seeing, but influence of moonlight). We obtained 12 Rc frames of 600 
seconds exposure time each. The afterglow is faintly detected in the 
complete stack.

days after trigger Exposure Rc dRc (statistical)

8.90324   12 x 600 23.64 0.36

Compared to the flattening of the decay noted by de Ugarte Postigo et al. 
(GCN 9051) and already hinted at in earlier TLS and Lick data (Kann et 
al., GCN 9041, Perley, GCN 9042), the decay has steepened again, an 
indication of a (jet?) break. On the other hand, the last TLS detection 
agrees well with the extrapolation of the earlier decay (Kann et al., GCN 
9041), indicating that the plateau may be a rebrightening/optical flare 
spanning a few days.

Due to increasing moonlight, no further TLS observations are planned.

This message may be cited.


GRB_name: GRB090401A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9064
SUBJECT: GRB 090401, Swift-BAT refined analysis
DATE:    09/04/01 05:39:25 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

G. Sato (ISAS), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), P. Schady (MSSL-UCL),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+713 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090401 (trigger #348128)
(Schady, et al., GCN Circ. 9062).  The BAT ground-calculated position is
RA, Dec = 350.920, 29.762 deg, which is 
   RA(J2000)  =  23h 23m 40.8s 
   Dec(J2000) = +29d 45' 44.1" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 38%.
 
The mask-weighted light curve starts out at T-20 sec when the burst location
first came into the BAT FOV during a planned-target slew maneuver.  There is
evidence for emission starting prior to burst coming to the FOV.  There are
two small peaks at T+0 and T+30 sec. Then comes the main emission
with a series of at least 7 overlapping peaks starting at ~T+95 sec and
returning to background at ~T+190 sec.  T90 (15-350 keV) is 112 +- 15 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-9.4 to T+160.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.70 +- 0.05.  The fluence in the 15-150 keV band is 1.1 +- 0.0 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+122.05 sec in the 15-150 keV band
is 10.9 +- 0.5 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/348128/BA/


GRB_name: GRB090328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9065
SUBJECT: GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
DATE:    09/04/01 08:47:35 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

K.Ivanov, S.Yazev, 
Irkutsk State University


E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parhomenko,
   Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinski, I.Zalognikh, T.Kopytova
Ural State University, Kourovka


There are 6 MASTER Very Wide Field cameras located at Kislovodsk and 
Irkutsk  with common FOW = 6000 square degrees 
(http://observ.pereplet.ru/).

One of the two  MASTER Very Wide Field Cameras located at Irkutsk
(D=50 mm, 2x1000 square degrees, 11 Mpx) has observed  ~20% 1-sigma Fermi
error box  (A. Goldstein, GCN 9056) with 1s exposure
during  all night: befoure, during and after GRB Time
without time gap between images.

Our unfiltered images are calibrated relative to Tycho stars (V).
The magnitude limit of the each emage is  ~9.1 m at the edge of FOW (some 
ising was attend at this night).

We do not detect OT inside 20% part of the error box.


We  conclude (in the case that GRB inside our FOW ):

1). the optical fluence during the short 0.3 s GRBurst is limited by

                        ~<=  3 x 10E-9 erg/cm_2

excluding possible  host galaxy absorbtion.

The event fluence (8-1000 keV) in this time interval is
(9.61 +/- 0.31)E-07 erg/cm^2 (A. Goldstein, GCN 9056).

So:

2).  Optical-Fluence/Gamma-Fluence(8-1000 keV) ~ < 1/300

The same ratio for long GRB080319B is

Optical-Fluence/Gamma-Fluence(8 - 1000 keV) ~ 1/140

(Naked Eye GRB, Racusin, Karpov et al., Nature, vol.455, 183, 2008).


The film of our observations  is available at

http://observ.pereplet.ru/images/GRB090320B/GRB090328B.gif

Black circles are the 1-sigma and 3-sigma 
error boxes (A. Goldstein, GCN 9056).


The reduction is continued.

The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090401B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9066
SUBJECT: GRB 090401B: Swift detection of a burst
DATE:    09/04/01 09:02:29 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

P. Schady (MSSL-UCL), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), O. Godet (U Leicester),
H. A. Krimm (CRESST/GSFC/USRA), J. Mao (INAF-OAB),
P. T. O'Brien (U Leicester), S. R. Oates (UCL-MSSL),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), A. M. Parsons (GSFC), P. Romano (INAF-IASFPA),
B. A. Rowlinson (U Leicester) and H. Ziaeepour (UCL-MSSL) report on
behalf of the Swift Team:

At 08:35:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090401B (trigger=348152).  The BAT on-board calculated 
location is RA, Dec 95.101d, -8.963d which is 
   RA(J2000)  =  06h 20m 24s
   Dec(J2000) = -8d 57' 47"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows at least four
overlapping peaks with a total duration of ~20 seconds. 
The peak count rate was ~55,000 counts/sec (15-350 keV), at ~8 sec
after the trigger. 

The XRT began observing the field at 08:36:37.9 UT, 73.2 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 95.0889, -8.9734 which is equivalent to:
   RA(J2000)  = 06h 20m 21.33s
   Dec(J2000) = -08d 58' 24.2"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 57 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 150 seconds with the White      
filter  starting 81 seconds after the BAT trigger. No credible      
afterglow candidate has  been found in the automatic analysis. The   
2.7'x2.7' sub-image covers 100% of  the XRT error circle. The typical 
3-sigma upper limit has been about 19.6 mag, although we note that 
there are two bright known sources within the XRT error circle that  
 may be confusing source detection. One of these sources appears to   
be brighter and slightly offset from the DSS position, suggesting the
possible detection of the optical afterglow. However, we shall need
more data to check for any variability. The coverage of the XRT error
circle by the  8'x8' region for the list of  sources generated
on-board is uncertain because the large number of sources  filled the
available telemetry. No correction has been made for the expected 
extinction   corresponding to E(B-V) of 0.67. 

Burst Advocate for this burst is P. Schady (ps AT mssl.ucl.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090401B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9067
SUBJECT: Swift/UVOT detection of GRB090401B
DATE:    09/04/01 09:39:08 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P.Schady (MSSL-UCL) and S.R.Oates report on behalf of the Swift/UVOT  
team

Following from the tentative UVOT afterglow detection of GRB090401B  
reported in Schady et al. (GCN 9066), we here report a fading by over  
two magnitudes between the two UVOT white finding charts, taken 792s  
apart at the following position

RA (J2000) = 06:20:21.11 (95.08775deg)
Dec (J2000) = -08:58:19.5 (-8.97199deg)

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence),  
suggesting this to be the optical afterglow of GRB090401B. This  
position falls on a known source, making absolute magnitudes and a  
precise localisation difficult at this stage, and further data will be  
required in order to carry out source subtraction.

The values quoted above are not corrected for the Galactic extinction  
due to the reddening of E(B-V)  = 0.67 in the direction of the burst  
(Schlegel et al. 1998). All photometry is on the UVOT photometry  
system described in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090401B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9068
SUBJECT: GRB 090401B: Swift-BAT refined analysis
DATE:    09/04/01 12:38:51 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. Stamatikos (GSFC/ORAU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
P. Schady (MSSL-UCL), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+914 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090401B (trigger #348152)
(Schady, et al., GCN Circ. 9066).  The BAT ground-calculated position is
RA, Dec = 95.095, -8.963 deg, which is 
   RA(J2000)  =  06h 20m 22.7s 
   Dec(J2000) = -08d 57' 47.1" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 67%.
 
The mask-weighted light curve shows several FRED-like peaks with the first
starting at ~T-0.4 sec.  The brightest peak is at ~T+7 sec with a long
exponential tail out to ~T+600 sec.  T90 (15-350 keV) is 183 +- 39 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-0.1 to T+326.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.37 +- 0.05.  The fluence in the 15-150 keV band is 1.0 +- 0.0 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+6.49 sec in the 15-150 keV band
is 23.1 +- 0.5 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/348152/BA/


GRB_name: GRB090401B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9069
SUBJECT: AGILE Gamma-ray detection of GRB 090401B
DATE:    09/04/01 13:17:12 GMT
FROM:    Marco Feroci at IASF/INAF  <feroci@iasf-roma.inaf.it>

E. Moretti, F. Longo, G. Barbiellini, E. Vallazza (INFN Trieste),  
A. Giuliani (INAF/IASF Milan), S. Cutini, C. Pittori (ASDC),
A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milan),
E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci, L. Pacciani,
P. Soffitta, E. Costa, F. Lazzarotto, I. Lapshov, M. Rapisarda 
(INAF/IASF Rome), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), 
S. Vercellone (INAF/IASF Palermo), A. Bulgarelli, F. Gianotti, 
M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi, 
M. Galli, (INAF/IASF Bologna), M. Tavani, G. Pucella, F. D'Ammando, 
V. Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini (INAF/IASF Rome), 
P. Picozza, A. Morselli (INFN Roma-2), M. Prest (Universita' 
dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), A.Rappoldi, 
P. Cattaneo (INFN Pavia) and P. Giommi, P. Santolamazza
F.Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team, 
report:

The gamma ray burst 090401B (Schady et al. GCN 9066 & 9067) occurred 
in the field of view of AGILE, approximately 41 deg off-axis. 
This 12-s long event was triggered and localized in one dimension by 
SuperAGILE. It was detected also by the AGILE/ACS and MCAL, with 
significant detection above 2.8 MeV.
  
A preliminary analysis of the Gamma-Ray Imaging Detector (GRID) data
in temporal and spatial coincidence with the GRB shows a significant 
excess of gamma-ray events above 30 MeV at the location of the event.

A more detailed analysis of the AGILE-GRID data is in progress.
More observations of this interesting burst are strongly encouraged.
 
This message may be cited.


GRB_name: GRB090401B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9070
SUBJECT: GRB 090401B: Enhanced Swift-XRT position
DATE:    09/04/01 13:51:40 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2409 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 090401B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 95.08773, -8.97244 which is equivalent
to:

RA (J2000): 06h 20m 21.06s
Dec (J2000): -08d 58' 20.8"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090401A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9071
SUBJECT: Konus-Wind observation of GRB 090401A
DATE:    09/04/01 15:45:45 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The most intense part of the long GRB 090401A (Swift-BAT trigger 
#348128: Schady et al., GCN 9062; Sato et al., GCN 9064) triggered 
Konus-Wind at T0=170.845 s UT (00:02:50.845).

The burst light curve shows a weak emission starting at ~T0-120s 
followed by the main multipeaked part at ~T0-24s, which had a duration 
of ~40s. There is a hint of an earlier emission.

As observed by Konus-Wind the burst
had a fluence of 2.14(-0.17, +0.19)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+7.648 s
of 2.79(-0.42, +0.44)x10^-6 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The spectrum of the most intense part
(from T0 to T0+16.640 s) can be fitted (in the 20 keV - 1 MeV
range) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.26(-0.14, +0.15),
and Ep = 218(-34, +51) keV (chi2 = 87.9/60 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.3 (chi2 = 87.9/59 dof).

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090401_T00170/


GRB_name: GRB090331A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9072
SUBJECT: GRB 
DATE:    09/04/01 15:51:31 GMT
FROM:    Ascension Camero-Arranz at NASA VP62/FECYT  <Ascension.Camero@uv.es>

Subject: GRB 090331: Fermi GBM detection



A. Camero-Arranz (NASA; FECYT) and C. Wilson-Hodge (NASA/MSFC), 
report  on behalf of the Fermi GBM Team:



"At 16:20:20.39 UT on 03 31 09, the Fermi Gamma-ray Burst Monitor (GBM) 
triggered and located GRB 090331 ( trigger 260209222/ 090331681). The on-
ground calculated location, using the Fermi GBM trigger data, is  
RA = 212.38,   Dec = -0.51 (J2000 degrees, equivalent to J2000 
14h 09m, -00d 31' ), with  a  statistical uncertainty of 6.7 degrees 
(radius, 1-sigma containment,  statistical only; there is additionally a 
systematic error which is currently  estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight  is 40 degrees. Since  the source 
is weak, the time-averaged spectrum is poorly constrained." 
ï»¿Subject: GRB 090331: Fermi GBM detection

A. Camero-Arranz (NASA; FECYT) and C. Wilson-Hodge (NASA/MSFC), 
report  on behalf of the Fermi GBM Team:

"At 16:20:20.39 UT on 03 31 09, the Fermi Gamma-ray Burst Monitor (GBM) 
triggered and located GRB 090331 ( trigger 260209222/ 090331681). The on-
ground calculated location, using the Fermi GBM trigger data, is  
RA = 212.38,   Dec = -0.51 (J2000 degrees, equivalent to J2000 
14h 09m, -00d 31' ), with  a  statistical uncertainty of 6.7 degrees 
(radius, 1-sigma containment,  statistical only; there is additionally a 
systematic error which is currently  estimated to be 2 to 3 degrees). The 
angle from the Fermi LAT boresight  is 40 degrees. Since  the source 
is weak, the time-averaged spectrum is poorly constrained." 


GRB_name: GRB090401B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9073
SUBJECT: GRB 090401B: Swift XRT Refined Analysis
DATE:    09/04/01 17:41:33 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

A. Rowlinson (U. Leicester) and P. Schady (MSSL-UCL) report on behalf of
the Swift-XRT team:

We have analysed 3.7 ks of XRT data for GRB 090401B (Schady et al. GCN
Circ. 9066), from 79 s to 7.2 ks after the BAT trigger. The data
comprise 1.3 ks in Windowed Timing (WT) mode and 2.4ks in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Osborne et al. (GCN. Circ 9070). The light curve can be modelled with
an initial power-law decay with an index of alpha=1.145 (+/-0.020),
followed by a break at T+474 s to an alpha of 1.409 (+0.028, -0.026).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.736 (+/-0.026). The
best-fitting absorption column is 3.68 (+/-0.12) x 10^21 cm^-2, in
excess of the Galactic value of 2.3 x 10^21 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.13 (+/-0.11) and a
best-fitting absorption column of 4.4 (+0.5, -0.4) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.5 x 10^-11 (8.4 x 10^-11) erg cm^-2
count^-1.

If the light curve continues to decay with a power-law decay index of
1.409, the count rate at T+24 hours will be 0.017 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.7 x
10^-13 (1.4 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00348152.

This circular is an official product of the Swift-XRT team.

[GCN OPS NOTE(02apr09):  Per author's request, the typo in the Subject line
of "080401B" was changed to "090401B".]


GRB_name: GRB090401B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9074
SUBJECT: Swift/UVOT observations of GRB090401B
DATE:    09/04/01 17:50:53 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) and S.R.Oates (MSSL-UCL) reports on behalf of the 
Swift/UVOT team:

Swift UVOT began settled exposures of GRB090401B (Schady et al, GCN 9066) 
82 s after the burst trigger, and detected a bright optical transient at 
the position reported in by Schady et al. (GCN 9067), consistent with the 
enhanced XRT error circle (Osborne et al, GCN 9070).

The source is detected in the white, v, b and u filter, but not in any of 
UV filters, placing an upper limit on the redshift of z < 3. We note that 
the afterglow lies close to a known source, which may be contaminating our 
phometry. The light curve decays steeply at early times at a rate of 
alpha_1~1.5, and then breaks at ~T+440s to a slope of alpha_2~0.7.

Using 2.5arcsec aperture, the magnitudes and 3 sigma upper
limits to our observations our reported below:

Filt    T_start (s)  T_stop (s)  Exp (s)  Mag/3-sig UL
white      82           232       147     16.83+/-0.02
white      874          1024      147     19.14+/-0.08
v          623          1248      78      18.31+/-0.20
v          4753         4953      197     19.10+/-0.25
b          549          1346      58      19.48+/-0.26
b          5573         5773      197     20.39+/-0.28
u          293          543       246     17.99+/-0.07
u          698          1312      58      18.67+/-0.22
uvw1       672          1297      78        > 19.42
uvm2       647          1272      78        > 18.99
uvw2       599          1387      78        > 19.39

The above magnitudes have not been corrected for the Galactic extinction 
corresponding to E(B-V) = 0.67 (Schlegel et al 1998). The photometry is on 
the UVOT flight system described in Poole et al (2008, MNRAS, 383,627)


GRB_name: GRB090401B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9075
SUBJECT: GRB 090401B: AGILE refined analysis
DATE:    09/04/01 17:52:03 GMT
FROM:    Sara Cutini at ASDC  <sara.cutini@asdc.asi.it>

A.Giuliani (INAF/IASF Milan), S.Cutini, C. Pittori (ASDC)
E. Moretti, F.Longo, G.Barbiellini, E.Vallazza (INFN Trieste),
M. Marisaldi, A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco,  
C. Labanti,
F. Fuschino, M. Galli, (INAF/IASF Bologna),
A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milan),
E. Del Monte, I. Donnarumma, Y.
Evangelista, M. Feroci, L. Pacciani, P. Soffitta, E. Costa,
F. Lazzarotto, I. Lapshov, M. Rapisarda(INAF/IASF Rome), A. Pellizzoni,
M. Pilia (INAF/OA Cagliari), S. Vercellone (INAF/IASF Palermo),
M. Tavani, G. Pucella,
F. D'Ammando, V.Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini
(INAF/IASF Rome), P. Picozza, A. Morselli (INFN Roma-2), M. Prest
(Universita'
dell'Insubria), P.Lipari, D. Zanello (INFN Roma-1), A.Rappoldi,  
P.Cattaneo
(INFN Pavia) and P. Giommi,  P. Santolamazza,
F.Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team,
report:

A more refined analysis of the AGILE-GRID (Gamma-Ray Imaging  
Detector) data of
GRB 090401B (Moretti et al. GCN 9069) confirms the gamma-ray  
detection of the
GRB  at energies above 30 MeV with a statistical significance larger  
than 4
for a 10-second integration after trigger.

Fluence estimate for a 10 second integration is 0.038+/-0.011 ph/cm2
(above 30 MeV).
The GRB 090401B gamma-ray spectrum appears to be relatively hard.

An estimate of fluence in the 500 keV - 10 MeV range, as
derived from MCAL data, is (1.6 +/- 0.5)e-5 erg/cm2 in the same time  
interval.

This message may be cited.


GRB_name: GRB090401B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9076
SUBJECT: Swift/UVOT observations of GRB090401B
DATE:    09/04/01 18:01:23 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) and S.R.Oates (MSSL-UCL) reports on behalf of the 
Swift/UVOT team:

Swift UVOT began settled exposures of GRB090401B (Schady et al, GCN 9066) 
82 s after the burst trigger, and detected a bright optical transient at 
the position reported in by Schady et al. (GCN 9067), consistent with the 
enhanced XRT error circle (Osborne et al, GCN 9070).

The source is detected in the white, v, b and u filter, but not in any of 
UV filters, placing an upper limit on the redshift of z < 3. We note that 
the afterglow lies close to a known source, which may be contaminating our 
phometry. The light curve decays steeply at early times at a rate of 
alpha_1~1.5, and then breaks at ~T+440s to a slope of alpha_2~0.7.

Using 2.5arcsec aperture, the magnitudes and 3 sigma upper limits to our 
observations our reported below:

Filt    T_start (s)  T_stop (s)  Exp (s)  Mag/3-sig UL
white      82           232       147     16.83+/-0.02
white      874          1024      147     19.14+/-0.08
v          623          1248      78      18.31+/-0.20
v          4753         4953      197     19.10+/-0.25
b          549          1346      58      19.48+/-0.26
b          5573         5773      197     20.39+/-0.28
u          293          543       246     17.99+/-0.07
u          698          1312      58      18.67+/-0.22
uvw1       672          1297      78        > 19.42
uvm2       647          1272      78        > 18.99
uvw2       599          1387      78        > 19.39

The above magnitudes have not been corrected for the Galactic extinction 
corresponding to E(B-V) = 0.67 (Schlegel et al 1998). The photometry is on 
the UVOT flight system described in Poole et al (2008, MNRAS, 383,627)


GRB_name: GRB090328A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9077
SUBJECT: GRB 090328: Fermi-LAT refined analysis
DATE:    09/04/01 19:30:09 GMT
FROM:    Sara Cutini at ASDC  <sara.cutini@asdc.asi.it>

Sara Cutini (ASDC), V. Vasileiou (NASA/GSFC, UMBC) and Jim Chiang  
(SLAC/KIPAC) report on behalf of the Fermi LAT team.

We report further analysis with the LAT data on GRB 090328 (McEnery  
et al. GCN Circ. 9044, Kennea et al. GCN Circ. 9045).
The emission in the LAT lasts up around 900s after the trigger, we  
did not find evidence for further high-energy delayed emission beyond  
900s.
Considering the rate of events passing the on board event filters for  
gamma-rays, the light curve shows a single pulse peaking at 25s which  
corresponds to the third spike of GBM light curve (A. Rau at al. GCN  
Circ. 9057).
The highest energy events detected by the LAT  which are  spatially  
coincident with the burst position arrived hundreds of seconds after  
the GRB trigger time.
In a preliminary time resolved spectral analysis we find no evidence  
of a change in spectral index during the whole duration of the burst.
The points of contact for this burst are Julie McEnery (LAT,  
julie.mcenery@nasa.gov) and Arne Rau (GBM, arau@mpe.mpg.de).
The Fermi LAT is a pair conversion telescope designed to cover the  
energy band from 20 MeV to greater than 300 GeV. It is the product of  
an international collaboration between NASA and DOE in the U.S. and  
many scientific institutions across France, Italy, Japan and Sweden.


GRB_name: GRB090401B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9078
SUBJECT: GRB 090401B: NOT optical observations
DATE:    09/04/01 22:10:33 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

D. Malesani, J.P.U. Fynbo (DARK/NBI), J. Heidt (Heidelberg), T. Liimets 
(Tartu Observatory), T. Pursimo (NOT), and P. Jakobsson (Univ. Iceland), 
report on behalf of a larger collaboration:

We observed the optical afterglow of GRB 090401B (Schady et al., GCN 
9066; Schady & Oates, GCN 9067), also detected by AGILE (Moretti et al., 
GCN 9069; Giuliani et al., GCN 9075). Observations were carried out in 
the R band with the Nordic Optical Telescope, starting on April 1.870 
UT, 12.3 hr after the GRB.

In a single 300 s exposure, the afterglow is clearly detected, with a 
magnitude R ~ 22.2 +- 0.1, referred to USNO-B1 stars in the neighbourhood.

We acknowledge excellent support from the NOT visiting observers and staff.


GRB_name: GRB090401B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9079
SUBJECT: GRB090401B, RIMOTS optical upper limits
DATE:    09/04/02 05:17:04 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

K.Kono, K.Noda, E.Sonoda, N.Ohmori, H.hayasi, 
A.Daikyuji, Y.Nisioka, M.Yamauchi
(University of Miyazaki)

 We have observed the field covering the error circle of
GRB090401B (Swift trigger 348152, GCN 9066, Schady et al.) 
with the unfiltered CCD camera on the 30-cm telescope 
at University of Miyazaki.
The observation was started 10:47:10 UT, about 1.8 hr
after the Swift trigger time.
We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog,
There is no new source at the reported position.
(GCN 9068, Stamatikos et al. GCN 9070, Osborne et al. )

the upper limits are as follows:
--------------------------------------------------------------
Start(UT)   End(UT)    Num. of frames    Limit (mag.)
--------------------------------------------------------------
11:41:47    11:42:17          1            16.8
11:41:47    12:32:21         43            17.7
---------------------------------------------------------------


GRB_name: GRB090401B
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9080
SUBJECT: GRB 090401B: Upper limits of MITSuME optical observation
DATE:    09/04/02 13:49:37 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

D. Kuroda, M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 090401B (Schady et al. GCN 9066)
with optical three color (g', Rc and Ic) CCD camera attached to
the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
We did not detect the optical afterglow reported by Schady and
Oates (GCN 9067; GCN 9074). 3-sigma upper limits to our
observation are listed below. We used GSC2.3 catalog for flux
calibration.

       Mid-UT         T(s)   EXP(s)      g'      Rc     Ic
-------------------------------------------------------------
2009-04-01 10:43:51   7706     660     >18.2   >18.1  >17.6
-------------------------------------------------------------


GRB_name: GRB090401B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9081
SUBJECT: GRB 090401B: VLA radio upper limit
DATE:    09/04/02 16:49:43 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on
behalf of the Caltech-NRAO-Carnegie GRB Collaboration:

"We used the Very Large Array to observe the field of view toward
GRB 090401B (GCN 9066) at a frequency of 8.46 GHz on 2009 Apr. 02.15
UT. The GRB radio afterglow is undetected at the Swift-UVOT position 
(GCN 9067). The three-sigma flux density of the GRB afterglow at the
Swift UVOT position is 138 uJy.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090401B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9082
SUBJECT: GRB 090401B: Xinglong TNT optical Upper Limit
DATE:    09/04/03 09:17:29 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

S.M. Hu, L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei,
j. Wang, J.S. Deng and J.Y. Hu on behalf of EAFON report:

We have observed GRB 090401B (Schady et al., GCN
9066; Schady & Oates, GCN 9067, GCN 9074)
with Xinglong TNT telescope from Apr.1, 11:25:22(UT),
3.37 hr after the burst. After combined 9*300s R
band images, no new source was found in our combined
image. The 3 sigma upper limits was obtained
to be R=19.9 mag at the mean time of 2.71 hr after 
the trigger, with the calibration to USNO-B1.0 R2 magnitude.

This message may be cited.

For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/


GRB_name: GRB090401B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9083
SUBJECT: Konus-Wind observation of GRB 090401B
DATE:    09/04/03 11:35:30 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The long bright GRB 090401B (Swift-BAT trigger #348152: Schady et al., 
GCN 9066; Stamatikos et al., GCN 9068) triggered Konus-Wind at 
T0=30922.964 s UT (08:35:22.964).

The burst light curve shows a multipeaked structure with a duration of
~11 s. There is a hint of an extended soft emission.

As observed by Konus-Wind the burst
had a fluence of 6.25(-0.75, +0.78)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+6.576 s
of 4.63(-0.86, +0.87)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+16.996 s) is well fitted (in the 20 keV - 10 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.78(-0.09, +0.11),
the high energy photon index beta = -2.14(-0.23, +0.15),
the peak energy Ep = 409(-60, +66) keV (chi2 = 61.8/85 dof).

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090401_T30922/


GRB_name: GRB090401B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9084
SUBJECT: GRB 090401B: Suzaku WAM observation of the prompt emission
DATE:    09/04/04 07:04:06 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka@phys.aoyama.ac.jp>

M. Suzuki, M. Ohno, M. Kokubun, T. Takahashi (ISAS/JAXA),
N. Kodaka, W. Iwakiri, M. Tashiro, Y. Terada, Y. Urata, A. Endo,
K. Onda, K. Morigami, T. Sugasahara (Saitama U.), T. Enoto,
K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka
(Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), T. Uehara,
T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.),
E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono,
H. Hayashi (Univ. of Miyazaki), S. Hong (Nihon U.), N. Vasquez
(Tokyo Tech.), on behalf of the Suzaku WAM team, report:

The bright long GRB 090401B (Swift/BAT trigger #348152; Schady et al. 
GCN 9066; Stamatikos et al., GCN 9068) triggered the Suzaku Wide-band 
All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV 
at 08:35:24.504 UT (=T0).

The observed light curve shows a multi-peaked structure
lasting from T0+0s to T0+10s with a duration (T90) of about 9 seconds. 
The fluence in 100 - 1000 keV was 2.56 (-0.11,+0.09) x 10^-5 erg/cm^2. 
The 1-s peak flux measured from T0+7s was 21.6 (-1.5,+1.3) photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0+0s to
T0+10s is well fitted by a single power-law with a photon index
of 2.22 (-0.09,+0.10) (chi^2/d.o.f = 24.9/25).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:
 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090401A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9085
SUBJECT: GRB 090401A: Suzaku WAM observation of the prompt emission
DATE:    09/04/04 08:27:36 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka@phys.aoyama.ac.jp>

M. Suzuki, M. Ohno, M. Kokubun, T. Takahashi (ISAS/JAXA),
N. Kodaka, W. Iwakiri, M. Tashiro, Y. Terada, Y. Urata, A. Endo,
K. Onda, K. Morigami, T. Sugasahara (Saitama U.), T. Enoto,
K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka
(Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), T. Uehara,
T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.),
E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono,
H. Hayashi (Univ. of Miyazaki), S. Hong (Nihon U.), N. Vasquez
(Tokyo Tech.), on behalf of the Suzaku WAM team, report:

The bright long GRB090401A (Swift/BAT trigger #348128; Schady et al., 
GCN 9062; Sato et al., GCN 9064) was detected by the the Suzaku Wide-band 
All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV 
at 00:02:34.509 UT (=T0).

The observed light curve shows a multi-peaked structure lasting from 
T0-5s to T0+38s.  There is also a weak precursor starting at ~T0-103s, 
 resulting in the total duration (T90) of about 112 seconds.
The fluence in 100 - 1000 keV was 1.37(-0.10,+0.08) x10^-5 erg/cm^2.
The 1-s peak flux measured from T0+27s was 5.1(-0.4,+0.5) photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-5s to
T0+38s is fitted by a single power-law with a photon index
of 2.14 (-0.13,+0.14) (chi^2/d.o.f = 21.4/24).
3 % systematic errors were included in low energy channels. 
All the quoted errors are at 90% confidence level. 

The light curves with 1-sec time resolution for this burst will be appeared at:
 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html


GRB_name: GRB090404A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9086
SUBJECT: GRB 090404: Swift detection of a burst
DATE:    09/04/04 16:07:58 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), S. R. Oates (UCL-MSSL),
K. L. Page (U Leicester), D. M. Palmer (LANL) and
B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team:

At 15:56:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090404 (trigger=348428).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 239.218, +35.500 which is 
   RA(J2000) = 15h 56m 52s
   Dec(J2000) = +35d 29' 59"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multiply-peaked
structure with a duration of about 80 sec and possible activity 
out to T+100 sec.  The peak count rate was ~3500 counts/sec 
(15-350 keV), at ~17 sec after the trigger. 

The XRT began observing the field at 15:57:57.8 UT, 87.3 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 239.2351, +35.5173 which is equivalent to:
   RA(J2000)  = 15h 56m 56.42s
   Dec(J2000) = +35d 31' 02.2"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 79 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 96 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.02. 

Burst Advocate for this burst is H. Ziaeepour (hz AT mssl.ucl.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090404A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9088
SUBJECT: GRB 090404: Enhanced Swift-XRT position
DATE:    09/04/04 21:31:18 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 989 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 090404, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 239.23986, +35.51615 which is equivalent
to:

RA (J2000): 15h 56m 57.57s
Dec (J2000): +35d 30' 58.1"

with an uncertainty of 1.8 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090404A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9089
SUBJECT: GRB 090404: Swift-BAT refined analysis
DATE:    09/04/04 23:48:55 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. Tueller (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
T. N. Ukwatta (GWU), H. Ziaeepour (UCL-MSSL)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090404 (trigger #348428)
(Ziaeepour, et al., GCN Circ. 9086).  The BAT ground-calculated position is
RA, Dec = 239.233, 35.518 deg, which is 
   RA(J2000)  =  15h 56m 55.8s 
   Dec(J2000) = +35d 31' 03.4" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 89%.
 
The mask-weighted light curve shows at least 7 overlapping peaks starting
at ~T-50 sec and ending at ~T+150 sec.  T90 (15-350 keV) is 84 +- 14 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-35.2 to T+94.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.32 +- 0.08.  The fluence in the 15-150 keV band is 3.0 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+17.32 sec in the 15-150 keV band
is 1.9 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/348428/BA/


GRB_name: GRB090404A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9090
SUBJECT: GRB 090404: Xinglong TNT optical Upper Limit
DATE:    09/04/04 23:49:27 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

GRB 090404: Xinglong TNT optical Upper Limit

L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei,
j. Wang, J.S. Deng, Y. Urata and J.Y. Hu 
on behalf of EAFON report:

We have observed GRB090404 (Ziaeepour et al., 
GCN 9086; Beardmore et al., GCN 9088)
with Xinglong TNT telescope from Apr.4,15:58:17 (UT),
107 sec after the burst. After combined 18*20s white
band images, no new source was found in our combined
image. The 3 sigma upper limits calibrated to USNO-B1.0 
R2 magnitude is R=20.37 mag at the mean time of 333 sec 
after the trigger.

This message may be cited.

For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/


GRB_name: GRB090404A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9091
SUBJECT: GRB 090404: Swift-XRT Team refined analysis
DATE:    09/04/05 00:01:05 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page (U. Leicester) & H. Ziaeepour (UCL-MSSL) report on behalf of the 
Swift-XRT team:

We have analysed the first 3 orbits of XRT data obtained for GRB 090404 
(Ziaeepour et al. 2009, GCN Circ. 9086), comprising 129 s in Windowed 
Timing mode and 5.4 ks in Photon Counting (PC) mode. The UVOT-enhanced 
position was given by Beardmore et al. (GCN Circ. 9088).

The X-ray afterglow was initially very bright, starting at a count rate of 
~1200 count s^-1. The light-curve can be approximately modelled with a 
doubley broken power-law: alpha1 = 3.2 +/- 0.3 until around 120 s after 
the burst, at which point the decay steepened to a slope of alpha2 = 9.3 
+/- 0.3. After 265 s, the decay is much more gradual, with alpha3 = 0.17 
+/- 0.06.

The data show significant softening until at least 150 s after the 
trigger. A spectrum extracted from the first orbit of PC data can be 
fitted with a power-law of Gamma = 3.0 +/- 0.5 and a total absorbing 
column of 5.1x10^21 cm^-2, which is in excess of the Galactic value of 
2.0x10^20 cm^-2 (Kalberla et al. 2005). The counts to observed 
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum 
is 3.1x10^-11 (1.4x10^-10) erg cm^-2 count^-1.

If the light-curve continues to decay with alpha ~ 0.17, the predicted 
count rate at 24 hours is 0.14 count s^-1, corresponding to an observed 
(unabsorbed) flux of 4.3x10^-12 (2.0x10^-11) erg cm^-2 s^-1. However, we 
note that it is unlikely that the light-curve decay will still be this 
flat at 24 hours.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_products/00348428.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090404A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9092
SUBJECT: GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
DATE:    09/04/05 00:34:01 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

P. Yock (Auckland Univ.), B. Allen (Vintage Lane Obs., Blenheim), , A. de
Ugarte Postigo (ESO Santiago), P. Kubnek (GACE, Univ. of Valencia), A.
Sota and A. J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger
collaboration, report:

"Following the detection by Swift of GRB 090404 (Ziaeepour et al. GCNC
9086), the 0.6-m Yock-Allen robotic telescope at the BOOTES-3 astronomical
station in Blenheim (New Zealand) responded automatically, under
non-favourable conditions (very high airmass). The first i'-band images
taken 185s after the trigger time (15:59:35 UT) set a limiting magnitude
of i' = 15 at this time. Follow-up observations at the 1.5-m telescope at
Observatorio de Sierra Nevada in Granada have been obtained starting at
21:46 UT. No optical afterglow in the I-band is detected at the Swift/XRT
enhanced position (Beardmore et al. GCNC 9088) down to the DSS2-infrared
limit.  A more detailed analysis is in progress."

This message can be quoted.


GRB_name: GRB090404A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9093
SUBJECT: GRB 090404: NOT observations
DATE:    09/04/05 03:21:10 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

D. Malesani, J.P.U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), A.J. 
Levan (Univ. Warwick), T. Liimets (Tartu Obs. and NOT), and Z. Banhidi 
(NOT), report on behalf of a larger collaboration:

We observed the field of GRB 090404 (Ziaeepour et al., GCN 9086) with 
the NOT equipped with StanCam. Observations were carried out in the R 
and I bands, starting on 2009 Apr 5.035 UT (8.89 hr after the GRB). A 
total of 20 min exposure per filter were secured.

We do not detect any object inside the revised XRT error circle 
(Beardmore et al., GCN 9088), down to limiting magnitudes R > 23.5, I > 
22.3, assuming R = 19.19 and I = 18.84 for the USNO-B1 star 1255-0233978 
at RA = 15:57:00.24, Dec = +35:31:28.0.

We note the presence of a faint object (R = 22.8), possibly extended, 
just outside the XRT circle, at coordinates (J2000):

RA = 15:56:57.72
Dec = +35:30:58.2

This position is 2.4" away from the XRT error circle center, which has 
currently an error radius of 1.4" (from 
http://www.swift.ac.uk/xrt_positions/index.php). We cannot state whether 
this object is related to GRB 090404. Further observations are ongoing.

[GCN OPS NOTE(06may09): Per author's request, the institutional
affiliation of Banhidi was changed to NOT.]


GRB_name: GRB090404A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9094
SUBJECT: Swift/UVOT observations of GRB090404
DATE:    09/04/05 12:56:40 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and H. Ziaeepour report on behalf of the Swift/UVOT 
team:

The Swift/UVOT began observing the field of GRB 090404 96 s after the BAT 
trigger (Ziaeepour et al., GCN Circ. 9086). No optical afterglow is 
detected in the initial UVOT exposures at the refined position of the 
X-ray afterglow (Beardmore et al., GCN Circ. 9088).

The 3 sigma upper limits for the finding chart (fc) and summed exposures 
are reported below.

Filter    T_start (s) T_stop  Exposure      Mag/3UL
---------------------------------------------------
white fc     96         246     147         < 20.92
white      591        1189    206         < 20.82
white        5121       18611   1084        < 21.80

u fc      310        559     246         < 20.17
u          715        1140    39          < 18.60
u            4710       35856  3049     < 21.56

v       641        1239    78          < 18.58
v            5531       11198  1150     < 20.37

b         565        1164    58          < 19.35
b            4915       35968  2078     < 21.50

uvw1         691        1116    39          < 18.45
uvw1         4504       45467  3237     < 21.47

uvm2       665        1091    58          < 18.54
uvm2         5736       41754  2695     < 21.42

uvw2       616        1214    78          < 19.09
uvw2         5326       6965   393      < 20.28

The above magnitudes are not corrected for the Galactic extinction 
corresponding to a reddening of E_{B-V} = 0.02 mag (Schlegel et al., 1998, 
ApJS, 500, 525).  The photometry is on the UVOT flight system described in 
Poole et al. (2008, MNRAS, 383,627).


GRB_name: GRB090404A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9095
SUBJECT: GRB 090404: further NOT observations
DATE:    09/04/05 18:51:36 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

D. Malesani (DARK/NBI), P. D'Avanzo (Univ. Bicocca/INAF-Brera), P.
Jakobsson (Univ. Iceland), J.P.U. Fynbo (DARK/NBI), T. Liimets (Tartu Obs.
and NOT), and Z. Banhidi (NOT), report on behalf of a larger
collaboration:

Further to what reported in GCN 9093 (Malesani et al.), we observed again
the field of GRB 090404 (Ziaeepour et al., GCN 9086) with the NOT. The
object just outside the error circle noted in GCN 9093 is still well
detected in the R band. Comparison of the two epochs, taken with mean
times Apr 5.043 and Apr 5.214 UT (9.09 and 13.19 hr after the GRB,
respectively), reveals no fading of the object by more than 0.1 mag. This
corresponda to a limit on the decay index alpha < 0.25 (assuming F propto
t^-alpha).

The lack of significant variability and the location of the object outside
the XRT error circle make this object unlikely related to GRB 090404.

We acknowledge the NOT staff for excellent support.

[GCN OPS NOTE(06may09): Per author's request, the institutional
affiliation of Banhidi was changed to NOT.]


GRB_name: GRB090404A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9096
SUBJECT: GRB 090404: GROND upper limits
DATE:    09/04/06 13:03:26 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

P. Afonso, T. Kruehler, J. Greiner (MPE Garching) and S. Klose 
(TLS Tautenburg), report on behalf of the GROND team:

GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI
telescope at La Silla Observatory (Chile), observed the field of GRB 090404 
(H. Ziaeepour et al. 2009, GCN #9086) simultaneously in the g'r'i'z'JHK bands.
Observations started on April 5, at 06:19 UTC (14.4 h after the burst) and
were carried out at air mass higher than 2.2.

We obtained several short exposures with a total integration time of 80 min
in g'r'i'z' and 72 min in JHK.

We do not detect any new object in the stacked images inside the enhanced XRT 
error circle (Beardmore et al. 2009, GCN #9088), down  to the following 
limiting magnitudes (all in the AB system):
  
g' > 23.8
r' > 24.3
i' > 23.3
z' > 23.1
J  > 22.3 
H  > 21.6 
K  > 20.3 
  
The upper limits have been obtained using SDSS and 2MASS field stars as 
reference. No correction has been made for the expected extinction 
corresponding to E(B-V) of 0.02 mag.

We further note that the nearby object reported by D. Malesani et al. (2009, 
GCN #9093) is present in the SDSS catalog, and also detected with GROND at
very similar magnitudes.


GRB_name: GRB090403A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9097
SUBJECT: GRB 090403: Fermi GBM detection
DATE:    09/04/06 15:22:07 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

Sheila McBreen (UCD/MPE)  reports on behalf of the Fermi GBM Team:

"At 07:32:42.13 UT on 03 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090403 (trigger 260436764 / 090403314).

The on-ground calculated location, using the GBM trigger
data, is RA = 65.2, DEC = +47.1 (J2000 degrees,
equivalent to 04 h 21 m, +47 d 06'), with an uncertainty
of 8.5 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 42 degrees.

The GBM light curve consists of one pulse
with a duration of about 16 s. Since the source is weak,
the time-averaged spectrum is poorly constrained."


GRB_name: GRB090405A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9098
SUBJECT: GRB 090405: Fermi GBM Detection
DATE:    09/04/06 16:34:41 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein@msfc.nasa.gov>

A. Goldstein (UAH) reports on behalf of the Fermi GBM Team: 

"At 15:54:41.34 UT on 05 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090405 (trigger 260639683 / 090405663).

The on-ground calculated location, using the GBM trigger 
data, is RA = 226.7, DEC = -5.6 (J2000 degrees, 
equivalent to 15h 07m, -05d 37'), with an uncertainty 
of 9.9 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 70 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM lightcurve consists of one peak with a duration of about 1.2 s.
Since the source is weak, the time-averaged spectrum is poorly
constrained."


GRB_name: GRB090404A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9099
SUBJECT: GRB 090404: nIR observations at Calar Alto
DATE:    09/04/06 22:05:09 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

M. Jelnek, A. J. Castro-Tirado (IAA-CSIC Granada) and G. Bergond (CAHA
Almera), on behalf of a larger collaboration, report:

"Following the detection by Swift of GRB 090404 (Ziaeepour et al. GCNC
9086), JHKs observations (900-s each) were conducted on Apr 5.025 UT (8.5
hr after the burst) with the 3.5-m telescope (+ OMEGA2000) at the
German-Spanish Calar Alto Observatory, under excellent conditions (0".9
seeing). At the Swift/XRT enhanced position (Beardmore et al. GCNC 9088)
no nIR source is detected down to a limiting magnitude H = 21.5, in
agreement with the limits reported by Afonso et al (GCNC 9096)."

This message can be quoted.


GRB_name: GRB090404A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9100
SUBJECT: GRB 090404: millimeter detection
DATE:    09/04/06 22:15:32 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

A. J. Castro-Tirado (IAA-CSIC Granada), M. Bremer and J.-M. Winters
(IRAM Grenoble), J. Gorosabel, S. Guziy, M. Jelnek, P. Kubnek
(IAA-CSIC), A. de Ugarte Postigo (ESO Santiago) and D. Prez-Ramrez
(Univ. de Jan), report:

"Following the detection by Swift of GRB 090404 (Ziaeepour et al. GCNC
9086), millimeter observations were conducted on Apr 5.9 UT at the Plateau
de Bure Interferometer. Consistent the Swift/XRT enhanced position
(Beardmore et al. GCNC 9088) we clearly detect a millimeter source with a
108 GHz flux density of 1.1 mJy at coordinates RA(2000) = 15:56:57.52,
Dec(2000) = +35:30:57.5 with (0.3",0.2") 1-sigma error in (RA,DEC).
Pending of confirming its variability we propose this as the likely
millimeter afterglow to GRB 090404. Together with the lack of optical and
near-IR afterglows (Xin et al. GCNC 9090, Yock et al. GCNC 9092, Malesani
et al. GCNC 9095, Afonso et al. GCNC 9096, Jelnek et al. GCNC 9099), this
event strongly resembles the dark burst GRB 051022 (Castro-Tirado et al.
2007, A&A 475, 101). Further millimeter observations are scheduled."

This message can be quoted.


GRB_name: GRB090407A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9101
SUBJECT: GRB 090407: Swift detection of a burst
DATE:    09/04/07 10:48:08 GMT
FROM:    David Burrows at PSU/Swift  <dxb15@psu.edu>

H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), O. Godet (U Leicester),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), N. P. M. Kuin (MSSL), J. Mao (INAF-OAB),
P. T. O'Brien (U Leicester), S. R. Oates (UCL-MSSL),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (INAF-IASFPA),
B. A. Rowlinson (U Leicester), B. Sbarufatti (INAF-IASFPA),
P. Schady (MSSL-UCL) and G. Stratta (ASDC) report on behalf of the
Swift Team:

At 10:28:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090407 (trigger=348650).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 68.959, -12.665 which is 
   RA(J2000) = 04h 35m 50s
   Dec(J2000) = -12d 39' 53"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multiple-peaked
structure with a duration of at least 150 sec, including a small
peak at T+135 sec, during the XRT/UVOT observations.  The peak count rate
was ~2390 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 10:29:58.7 UT, 93.0 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 68.98074, -12.67921 which
is equivalent to:
   RA(J2000)  = 04h 35m 55.38s
   Dec(J2000) = -12d 40' 45.2"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 91 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.68e+20
cm^-2, Kalberla et al. 2005), with an excess column of 2.5
(+1.79/-1.62) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White 
filter  starting 97 seconds after the BAT trigger. No credible 
afterglow candidate has  been found in the initial data products. The
2.7'x2.7' sub-image covers 25% of the BAT error circle and 0% of the
XRT error circle. The typical 3-sigma upper limit has been about 19.6
mag. The 8'x8'  region for the list of sources generated on-board
covers 100% of the  BAT and XRT error circles. The list of sources is
typically complete to about  18 mag. No correction has been made for
the expected extinction  corresponding to E(B-V) of 0.07. 

Burst Advocate for this burst is H. Ziaeepour (hz AT mssl.ucl.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090407A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9102
SUBJECT: GRB 090407: ROTSE-III Optical Limits
DATE:    09/04/07 11:06:47 GMT
FROM:    Brad Schaefer at LSU  <schaefer@grb.phys.lsu.edu>

B. E. Schaefer (Louisiana State), F. Yuan (U Mich), report on behalf of 
the ROTSE collaboration:

ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to
GRB 090407 (Swift trigger 348650; H. Ziaeepour et al., GCN 9101),
producing images beginning 8.8 s after the GCN notice time. An automated
response took the first image at 10:29:05.8 UT, 40.2 s after the burst,
and during the gamma-ray emission, under fair conditions. We took 10
5-sec, 10 20-sec and 33 60-sec exposures. These unfiltered images are
calibrated relative to USNO A2.0 (R). Imaging is on going but the 
source is getting low.

Comparison to the DSS (second epoch) reveals no new sources within the 
3-sigma Swift/BAT error circle or the XRT error circle, for both single 
images and coadding into sets of 10; the field is not crowded. Individual 
images have limiting magnitudes ranging from 13.9-15.5; we set the 
following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
10:29:05.8   10:29:10.8         5     14.1           40.2       N
10:29:05.8   10:31:19.0       133     16.1           40.2       Y


GRB_name: GRB090406A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9103
SUBJECT: Konus-Wind and Konus-RF observations of GRB 090406
DATE:    09/04/07 16:37:56 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
P. Oleynik, M. Ulanov, and D. Svinkin on behalf of
the Konus-Wind and Konus-RF teams, and
T. Cline on behalf of the Konus-Wind team, report:

The long bright GRB 090406  triggered Konus-Wind
at T0=62531.417 s UT (17:22:11.417),
and Konus-RF instrument onboard CORONAS-PHOTON s/c
at T0=62535.495 s UT (17:22:15.495).

The burst light curve shows a smooth single-peaked structure
with a duration of ~12 s.

--
As observed by Konus-Wind the source of the burst
is in the south ecliptic hemisphere
at ecliptic latitude of -46.5 +/- 3 degrees.
The burst had a fluence of 6.6(-0.26, +0.17)x10-5 erg/cm2,
and a 0.256-ms peak flux measured from T0+1.536 s
of 2.1(-0.15, +0.14)x10-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+15.616 s) is well fitted
(in the 20 keV - 2 MeV range) by GRB (Band) model
for which:
the low-energy photon index alpha = -1.04 +/- 0.05,
the high energy photon index beta = -2.69(-0.29, +0.19),
the peak energy Ep = 241(-15, +16) keV (chi2 = 53.4/58 dof).

--
As observed by Konus-RF the burst
had a fluence of 7.3(-0.23, +0.11)x10-5 erg/cm2,
and a 0.300-ms peak flux measured from T0+0.600 s
of 2.2(-0.16, +0.14)x10-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0-0.800 to T0+10.500 s) is well fitted
(in the 20 keV - 2 MeV range) by GRB (Band) model
for which:
the low-energy photon index alpha = -0.86 +/- 0.03,
the high energy photon index beta = -2.54(-0.13, +0.10),
the peak energy Ep = 228(-10, +11) keV (chi2 = 153/133 dof).

--
Due to uncertainties in the burst incident angles
the quoted values are preliminary. All the quoted errors
are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090406_T62531/


GRB_name: GRB090407A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9104
SUBJECT: GRB 090407: Swift-BAT refined analysis
DATE:    09/04/07 19:52:15 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (GWU) S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), H. Ziaeepour (UCL-MSSL)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+627 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090407 (trigger #348650)
(Ziaeepour, et al., GCN Circ. 9101).  The BAT ground-calculated position is
RA, Dec = 68.979, -12.684 deg, which is 
   RA(J2000)  =  04h 35m 54.9s 
   Dec(J2000) = -12d 41' 02.4" 
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 84%.
 
The mask-weighted light curve shows two clusters of peaks.  The first cluster
starts at ~T-15 sec, peaks at ~T+2 sec, and returns to baseline at ~T+10 sec.
The second clutser starts at ~T+130 sec, peaks at ~T+140 sec, and returns
to baseline at ~T+340 sec.  T90 (15-350 keV) is 310 +- 70 sec
(estimated error including systematics).
 
The time-averaged spectrum from -17.7 to 368.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.73 +- 0.29.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.45 sec in the 15-150 keV band
is 0.6 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/348650/BA/


GRB_name: GRB090407A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9105
SUBJECT: GRB 090407: Enhanced Swift-XRT position
DATE:    09/04/07 19:56:04 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 8297 s of XRT Photon Counting mode data and 13 UVOT
images for GRB 090407, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 68.97908, -12.67929 which is equivalent
to:

RA (J2000): 04h 35m 54.98s
Dec (J2000): -12d 40' 45.5"

with an uncertainty of 1.4 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090407A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9106
SUBJECT: GRB 090407: Swift UVOT Upper Limits
DATE:    09/04/07 21:34:44 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R.  Oates (MSSL-UCL) and H. Ziaeepour (MSSL-UCL) report on behalf  
of the Swift/UVOT team:

The Swift/UVOT began observing the field of GRB 090407 98 s
after the BAT trigger (Ziaeepour et al., GCN Circ. 9101). No
optical afterglow is detected in the initial UVOT exposures at
the refined position of the X-ray afterglow (Evans et al., GCN Circ.  
9105).

The 3 sigma upper limits for the finding chart (fc) and summed
exposures are reported below.

Filter    T_start (s) T_stop  Exposure      Mag/3UL
------------------------------------------------------------
white fc    98          248          147         <20.50
u fc           310       559          246         <19.89
white        590       2050        303         <21.04
v               640        5550        352         <19.25
u              713        2001        136         <19.61
b              565        2026        156         <19.99
uvw1       689         1977        136         <19.35
uvm2       664        5607        207         <19.49
uvw2       615         2071        170         <19.74
 

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} =  0.40 mag (Schlegel et al.,
1998, ApJS, 500, 525).  The photometry is on the UVOT photometric system
described in Poole et al. (2008, MNRAS, 383,627).


GRB_name: GRB090407A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9107
SUBJECT: GRB 090407: Swift-XRT refined analysis
DATE:    09/04/08 00:10:35 GMT
FROM:    Andy Beardmore at U Leicester  <apb@star.le.ac.uk>

A.P. Beardmore (U. Leicester) and H. Ziaeepour (UCL-MSSL) report on 
behalf of the Swift-XRT team:

We have analysed the first five orbits of Swift-XRT data obtained from
GRB 090407 (trigger #348650; Ziaeepour, et al., GCN Circ. 9101),
comprising 273 s taken in Windowed Timing (WT) mode, starting at
T+96.7 s, followed by 10.2 ks in Photon Counting (PC) mode from 
T+398 s to T+24.2 ks. The UVOT-enhanced position was given by Evans 
et al. (GCN Circ. 9105).

The 0.3-10 keV X-ray light curve shows a number of flares in the first
400 s, the largest occurring from T+120 s to T+180 s, reaching a peak
rate of 90 count s^-1 at T+140 s. This flare is also seen by the
Swift-BAT (Ukwatta et al., GCN Circ. 9104).  Further flaring is seen
from ~T+200s to ~T+350 s, ending with a steep decay of slope
~4.0. After T+950 s the X-ray light curve breaks to a much shallower
decay slope of 0.28 +/- 0.06.

The data show spectral evolution during the flaring intervals, after
which the PC mode spectrum can be modelled by an absorbed powerlaw
with a photon index of 2.43 +/- 0.13 and a total absorbing column
density of (2.51 +/- 0.35) x 10^21 cm^-2, which is in excess of the
Galactic value of 3.7 x 10^20 cm^-2 (Kalberla et al. 2005) in the
direction of the burst. The observed 0.3-10 keV flux at this time
(~T+6.2 ks) is (6.29 +0.41 -0.56) x 10^-12 erg cm^-2 s^-1, which
corresponds to an unabsorbed flux of 1.3 x 10^-11 erg cm^-2 s^-1. The
count to observed flux conversion factor for this spectrum is 
3.5 x 10^-11 erg cm-^2 count^-1.

If the light curve continues to decay with the same slope of 0.28 we
predict an X-ray count rate of 0.047 count s^-1 at T+24 hours after
the trigger, which corresponds to an observed 0.3-10 keV flux of 
1.6 x 10^-12 erg cm^-2 s^-1.  However, we  note that it is unlikely 
the light curve decay will remain this shallow at T+24 hours.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_curves/00348650.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090407A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9108
SUBJECT: GRB 090407: VLT observations
DATE:    09/04/08 01:02:57 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Daniele Malesani and Johan Peter Uldall Fynbo report on behalf of a 
larger collaboration:

We observed the field of GRB 090407 (Ziaeepour et al., GCN 9101) with 
the ESO VLT equipped with FORS2. Observations were carried out with mean 
time Apr 8.0 UT (13.7 hr after the GRB), partially during evening twilight.

Inside the X-ray error circle (Evans et al., GCN 9105), no source is 
detected down to limiting magnitudes R > 23.8 and z(AB) > 23.8, based on 
archival zeropoints (accurate up to ~0.2 mag).

We encourage deeper observations, possibly in the near infrared.

We acknowledge significant support from the ESO staff at Paranal, in 
particular Gianni Marconi and Elena Mason.


GRB_name: GRB090407A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9109
SUBJECT: GRB 090407: GROND upper limits
DATE:    09/04/08 02:19:56 GMT
FROM:    Paulo M. J. Afonso at MPE  <pafonso@mpe.mpg.de>

P. Afonso, F. Olivares, J. Greiner and T. Kruehler (MPE Garching) report
on behalf of the GROND team: 

GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI
telescope at La Silla Observatory (Chile), observed the field of GRB 090407
(H. Ziaeepour et al. 2009, GCN #9101) simultaneously in the g'r'i'z'JHK
bands. 

Observations started on April 7, at 23:34 UTC (13.1 h after the burst)
and lasted for 87 minutes. 

In stacked images of 24 min total integration time in griz and 20 min in 
JHK, we do not detect any new object inside the enhanced XRT error circle
(Evans et al., GCN #9105), down to the following limiting magnitudes
(all in the AB system): 

g' > 23.7
r' > 24.1
i' > 23.5
z' > 23.3
J  > 21.6
H  > 21.0
K  > 20.4 

The upper limits have been obtained using GROND zero points and 2MASS
field stars as reference. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.07 mag. 


GRB_name: GRB090408A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9110
SUBJECT: GRB 090408: Swift detection of a burst
DATE:    09/04/08 15:17:41 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. C. Stroh (PSU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU),
P. A. Evans (U Leicester), O. Godet (U Leicester), D. Grupe (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), J. L. Racusin (PSU), P. Romano (INAF-IASFPA),
B. Sbarufatti (INAF-IASFPA) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 15:02:11 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090408 (trigger=348720).  Swift will execute a delayed slew
to the burst.  The BAT on-board calculated location is 
RA, Dec 231.618, +37.564, which is 
   RA(J2000)  =  15h 26m 28s
   Dec(J2000) = +37d 33' 51"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT TDRSS light curve shows nothing significant
as is typical for an image trigger. 

Due to an observing constraint, Swift will not slew until 
T0+55 minutes. There will be no XRT or UVOT data until
this time. 

Burst Advocate for this burst is M. C. Stroh (stroh AT astroh.org). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090408B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9111
SUBJECT: GRB 090408B: MASTER II-Kourovka optical observations 
DATE:    09/04/08 18:33:14 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

V.Krushinski, I.Zalognikh, T.Kopytova
Ural State University, Kourovka

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parhomenko,
   Kislovodsk Solar Station of the Pulkovo Observatory


K.Ivanov, S.Yazev, Irkutsk State University


The MASTER II Wide Field Telescope located at Kourovka Observatory (Ural)
(two telescopes with D=400 mm, FOW = 2x4 square degrees, 2x16 Mpx CCD on 
one NTM mount) has observed  Swift error box  (Stroh et al., GCN 9110)
with 60s exposure started at 1h 27m after Trigger time 
(after sun set) simultaneously in two filters R and V.
MASTER-II is the new site of the MASTER-Net (http://observ.pereplet.ru/).
Actually, we observed from the city.

Our  images are calibrated relative to USNO B (R) & Tycho stars (V).
The wether is not very good.

We do not detect OT inside error box brighter ~17m (S/N=6).

The reduction is continued.

The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090408A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9114
SUBJECT: GRB 090408: Xinglong TNT optical Upper Limit
DATE:    09/04/09 05:06:27 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei, J. Wang, 
J.S. Deng, Y. Urata and J.Y. Hu on behalf of EAFON report:

We have observed GRB 090408 (Stroh et al., GCN 9110)
with Xinglong TNT telescope from  Apr.8,16:27:30 (UT),
1.42 hour after the burst. After combined 18*300s R
band images, no new source was found in our combined
image. The 3 sigma upper limits derived from  USNO-B1.0 
R2 magnitude is R=21.1 mag at the mean time of 1.67 hour
since the trigger.

This message may be cited.

For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/


GRB_name: GRB090408A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9115
SUBJECT: GRB090408, RIMOTS optical upper limits
DATE:    09/04/09 09:40:27 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

K.Kono, E.Sonoda, N.Ohmori, H.hayasi, 
A.Daikyuji, Y.Nisioka, K.Noda, M.Yamauchi
(University of Miyazaki)

 We have observed the field covering the error circle of
GRB090408 (Swift trigger 348720, GCN 9110, M.C.Stroh et al.) 
with the unfiltered CCD camera on the 30-cm telescope 
at University of Miyazaki.
The observation was started 15:05:13 UT (2 min. after the Swift trigger), 
under cloudy condition.
First analyzable image was obtained at 15:16:52 UT (14 min. after the Swift trigger). 

We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog,
There is no new source at the reported position.
(GCN 9110,M.C.Stroh et al.)

the upper limits are as follows:
--------------------------------------------------------------
Start(UT)   End(UT)    Num. of frames    Limit (mag.)
--------------------------------------------------------------
15:16:52    15:17:22          1            13.5
15:16:52    15:33:25         14            16.5
---------------------------------------------------------------


GRB_name: GRB090406A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9116
SUBJECT: GRB 090406: pseudo-z= 0.91 from prompt emission spectrum
DATE:    09/04/09 09:43:25 GMT
FROM:    Alexandre Pelangeon at LATT,CNRS,U. Toulouse  <alexandre.pelangeon@gmail.com>

A. Pelangeon & J-L. Atteia (LATT-OMP) report:

We used the spectral parameters of GRB 090406
provided by Golenetskii et al. (GCNC 9103)
to compute the spectral pseudo-redshift(**) of this burst
detected by Konus-Wind and Konus-RF instrument.


We find a pseudo-redshift pz= 0.91 +/- 0.10


** cf. http://www.ast.obs-mip.fr/grb/pz


GRB_name: GRB090409A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9119
SUBJECT: GRB 090409: Fermi GBM detection
DATE:    09/04/09 17:03:04 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

E. Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 06:54:01.44 UT on 09 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090409 (trigger 260952843 / 090409288).

The on-ground calculated location, using the GBM trigger
data, is RA = 302.1, DEC = +1.1 (J2000 degrees,
equivalent to 20h 08m, 01d 06'), with an uncertainty
of 7.9 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 90 degrees.

This weak and long GRB consists of a single peak
with a duration (T90) of about 20 s (8-1000 keV).
The time-averaged spectrum from T0 to T0+5.1 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is 1.2 +/- 0.7 and
the cutoff energy, parameterized as Epeak, is 137 +/- 17 keV
(chi squared 346 for 356 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(6.14 +/- 0.26)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4 s in the 8-1000 keV band
is 1.36 +/- 0.14 ph/s/cm^2.


The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090408A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9120
SUBJECT: GRB090408 : TAOS optical observations
DATE:    09/04/10 07:28:36 GMT
FROM:    Kuiyun Huang at ASIAA  <ljhuang@asiaa.sinica.edu.tw>

GRB090408 : TAOS optical observations

S.K. King, K.Y. Huang, S.Y. Wang and the TAOS team

The four 50cm TAOS telescopes observed GRB 090408 position (Stroh et
al, GCN9110) at 91s after the burst. No new optical emission was
detected in the BAT possition error range. The 3-sigma limiting
magnitude, compared with USNOB red stars, are as follows:

------------------------------------------------------------------------------
  Mean Dealy(s)   Exposure time   Limit mag.  Telescope
-------------------------------------------------------------------------------
    157            5s x15             15.2         TAOSB
    221.5          1s x60             14.8         TAOSD
--------------------------------------------------------------------------------


-- 
Lijin (Kuiyun) Huang
Postdoctoral Fellow
Institute of Astronomy & Astrophysics, Academia Sinica (ASIAA)
Phone: 886-2-3365 2200 x728


GRB_name: GRB090408B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9121
SUBJECT: Konus-Wind and Konus-RF observations of GRB 090408b
DATE:    09/04/10 14:40:32 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
P. Oleynik, M. Ulanov, and D. Svinkin on behalf of
the Konus-Wind and Konus-RF teams, and
T. Cline on behalf of the Konus-Wind team, report:


The very bright long GRB 090408b  triggered Konus-Wind
at T0=71198.539 s UT (19:46:38.539),
and Konus-RF instrument onboard CORONAS-PHOTON s/c
at T0=71203.482 s UT (19:46:43.482).

We have triangulated this burst to a preliminary
Konus-Wind - Konus-RF annulus centered at
RA(2000)=41.01, Dec(2000)=+14.92,
whose radius is 11.6  1.3 deg (3 sigma).

The Konus-Wind and Konus-RF light curves of this GRB are available
at http://www.ioffe.ru/LEA/GRBs/GRB090408_T71198/
They show a multipeaked structure with a duration of ~8 s.
The burst demonstartes strong spectral evolution,
as observed by Konus-RF a hard part of the burst emission
(above 500 keV) consists of several relatively narrow peaks,
while soft emission time profile is more smooth.
No emission is seen above 2500 kev.

The time-integrated spectrum of the most intense part of the event
(measured by Konus-Wind from T0 to T0+5.632 s)
can be fitted (in the 20 - 2500 keV range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.67(-0.04, +0.04),
the high energy photon index beta = -2.68(-0.09, +0.08),
the peak energy Ep = 344(-14, +13) keV (chi2 = 107/61 dof).

The spectrum of the most intense peak
(measured by Konus-Wind from T0+2.816 to T0+3.082 s)
is well fitted (in the 20 - 2500 keV range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.49 +/-0.09,
the high energy photon index beta = -2.94 (-0.28, +0.20),
the peak energy Ep = (431 +/- 30) keV (chi2 = 54/61 dof).

The burst had a fluence of (2.84 +/- 0.17)x10-4 erg/cm2,
and a 16-ms peak flux measured from T0+2.912 s
of 3.4(-0.8, +0.6)x10-4 erg/cm2/s
(both in the 20 - 2500 keV energy range).

Due to uncertainties in the burst incident angles
the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.


GRB_name: GRB090410A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9122
SUBJECT: GRB 090410: Swift detection of a burst
DATE:    09/04/10 17:10:20 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

D. Grupe (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
M. M. Chester (PSU), J. R. Cummings (NASA/UMBC),
N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
N. P. M. Kuin (MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (PSU), M. H. Siegel (PSU), M. Stamatikos (NASA/ORAU),
M. C. Stroh (PSU) and T. N. Ukwatta (GSFC/GWU) report on behalf of
the Swift Team:

At 16:57:52 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090410 (trigger=348929).  Swift could not slew to the GRB
due to a Sun constraint. The BAT on-board calculated location is 
RA, Dec 334.980, +15.471 which is 
   RA(J2000) = 22h 19m 55s
   Dec(J2000) = +15d 28' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex peak
from T-10 to T+40, followed by another broad peak from T+80 to T+140. 
The peak count rate was ~6000 counts/sec (15-350 keV), at ~6 
sec after the trigger. 

Swift cannot slew to the BAT position.  The burst is  sun-constrained
until Tuesday, 2009 April 14.  There will thus be no XRT or UVOT 
data for this trigger. 

Burst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090410A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9123
SUBJECT: GRB 090410: Swift-BAT refined analysis
DATE:    09/04/10 23:59:04 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S.D. Barthelmy (GSFC), W.H. Baumgartner (GSFC/UMBC), J.R. Cummings (GSFC/UMBC),
E.E. Fenimore (LANL), N. Gehrels (GSFC), D. Grupe (PSU),
H.A. Krimm (GSFC/USRA), C.B. Markwardt (GSFC/UMD), D.M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data sets from T-240 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090410 (trigger #348929)
(Grupe, et al., GCN Circ. 9122).  The BAT ground-calculated position is
RA, Dec = 334.956, 15.419 deg, which is 
   RA(J2000)  =  22h 19m 49.4s 
   Dec(J2000) = +15d 25' 08.6" 
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows two main peaks with some precursor activity.
The precursor activity starts at ~T-55 sec.  And because the target location
only came into the BAT FOV at T-110 sec, there may have been even earlier activity.
The first main peak started at ~T-10 sec, peaked at ~T+7 sec, and ended 
around T+45 sec.  The second main peak started at ~T+80 sec, peaked at ~T+120 sec,
and returned to baseline T+170 sec.  The burst location left the BAT FOV
at ~T+390 sec.  T90 (15-350 keV) is 165 +- 8 sec (estimated error
including systematics).
 
The time-averaged spectrum from T-49.2 to T+139.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.19 +- 0.05.  The fluence in the 15-150 keV band is 5.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+8.90 sec in the 15-150 keV band
is 1.9 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/348929/BA/


GRB_name: GRB090328B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9124
SUBJECT: GRB 090328b:  IPN Triangulation
DATE:    09/04/12 09:28:01 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
and T. Cline on behalf of the Konus-Wind and Konus-RF teams,

K. Hurley and T. Cline, on behalf of the Mars Odyssey
and Konus GRB teams,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team,

A. von Kienlin, G. Lichti, and A. Rau, and K. Hurley on behalf of the
INTEGRAL SPI-ACS team,

E. Costa, E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci,
I. Lapshov, F. Lazzarotto, L. Pacciani, M. Rapisarda, P. Soffitta,
for the SuperAGILE team,

G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, M. Marisaldi,
on behalf of the AGILE MCAL team report:


Konus-Wind, Konus-RF, Mars-Odyssey (GRS and HEND), and INTEGRAL-SPI-ACS
observed the intense GRB 090408b (Golenetskii et al., GCN 9121).  It was
also observed by AGILE-MCAL and SuperAGILE (outside the coded field of view).

We have triangulated it to the following 3-sigma error box:

-----------------------------------------------
        RA(2000), deg            Dec(2000), deg
-----------------------------------------------
Center:
    43.98 (02h 55m 56s)    +26.61 (+26d 36' 36")
Corners:
    43.95 (02h 55m 48s)    +27.59 (+27d 35' 24")
    42.98 (02h 51m 55s)    +27.78 (+27d 46' 48")
    44.05 (02h 56m 12s)    +25.64 (+25d 38' 24")
    44.97 (02h 59m 53s)    +25.49 (+25d 29' 24")
-----------------------------------------------

The error box area is 1.48 sq. deg.
This error box may be improved.

IPN triangulation map is avalable at
at http://www.ioffe.ru/LEA/GRBs/GRB090408_T71198/IPN
-- 


GRB_name: GRB090408B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9125
SUBJECT: GRB 090408b:  IPN Triangulation
DATE:    09/04/12 10:22:03 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
and T. Cline on behalf of the Konus-Wind and Konus-RF teams,

K. Hurley and T. Cline, on behalf of the Mars Odyssey
and Konus GRB teams,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team,

A. von Kienlin, G. Lichti, and A. Rau, and K. Hurley on behalf of the
INTEGRAL SPI-ACS team,

E. Costa, E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci,
I. Lapshov, F. Lazzarotto, L. Pacciani, M. Rapisarda, P. Soffitta,
for the SuperAGILE team,

G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, M. Marisaldi,
on behalf of the AGILE MCAL team report:


Konus-Wind, Konus-RF, Mars-Odyssey (GRS and HEND), and INTEGRAL-SPI-ACS
observed the intense GRB 090408b (Golenetskii et al., GCN 9121).  It was
also observed by AGILE-MCAL and SuperAGILE (outside the coded field of view).

We have triangulated it to the following 3-sigma error box:

-----------------------------------------------
         RA(2000), deg            Dec(2000), deg
-----------------------------------------------
Center:
     43.98 (02h 55m 56s)    +26.61 (+26d 36' 36")
Corners:
     43.95 (02h 55m 48s)    +27.59 (+27d 35' 24")
     42.98 (02h 51m 55s)    +27.78 (+27d 46' 48")
     44.05 (02h 56m 12s)    +25.64 (+25d 38' 24")
     44.97 (02h 59m 53s)    +25.49 (+25d 29' 24")
-----------------------------------------------

The error box area is 1.48 sq. deg.
This error box may be improved.

IPN triangulation map is avalable at
at http://www.ioffe.ru/LEA/GRBs/GRB090408_T71198/IPN
-- 


GRB_name: GRB090410A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9126
SUBJECT: GRB 090410: MITSuME optical upper limits
DATE:    09/04/13 08:31:45 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 090410 (Grupe et al. GCN 9122;
Barthelmy et al. GCN 9123) with optical three color (g', Rc and
Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama
Astrophysical Observatory. We started the observation at 18:12:59
UT, 4507s after the alert. We did not detect any new point source
within the BAT error circle (Barthelmy et al. GCN 9123). 3-sigma
upper limits to our observation are listed below. We used GSC2.3
catalog for flux calibration.

       Mid-UT           Td       EXP-T      g'     Rc    Ic
-------------------------------------------------------------
2009-04-10 18:57:15   7163sec   72x60sec  >17.9  >18.1  >18.5
-------------------------------------------------------------


GRB_name: GRB090410A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9128
SUBJECT: GRB 090410: GROND upper limits
DATE:    09/04/14 16:18:34 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

P. Afonso, T. Kruehler, A. Rau and J. Greiner (MPE Garching), report on 
behalf of the GROND team:

GROND (Greiner et al. 2008, PASP 120, 405), the 7-channel imager mounted at 
the 2.2m ESO/MPI telescope at La Silla Observatory (Chile) started 
follow-up observations of GRB 090410 (Grupe et al. 2009, GCN #9122) on April 
11, at 10:17 UTC (17.3 h after the burst). In addition, a second epoch of 
imaging was obtained, which started on April 12, 10:10 UTC.

Observations were performed at high airmass (~2.5) and limited to a total 
of 4 min exposures in each J, H and K in both epochs because of Sun 
constraints.

We do not detect any new object with respect to 2MASS inside the enhanced 
BAT error circle (Barthelmy et al. 2009, GCN #9123), and image subtraction 
between the two epochs does not reveal any obvious variable source. Upper 
limits from the first observation are as follows (all in the AB system):

J > 19.1 mag
H > 19.0 mag
K > 18.1 mag

The upper limits have been obtained using 2MASS field stars as reference. 
The given magnitudes are not corrected for the expected Galactic foreground 
extinction of E(B-V) of 0.05 mag.


GRB_name: GRB090410A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9129
SUBJECT: GRB 090410: Suzaku WAM observation of the prompt emission
DATE:    09/04/16 13:21:12 GMT
FROM:    Masanori Ohno at ISAS/JAXA  <ohno@astro.isas.jaxa.jp>

W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa
(RIKEN),
T. Uehara, T. Takahashi, Y. Fukazawa, Y. Hanabata (Hiroshima U.),
E. Sonoda, M. Yamauchi, N. Ohmori, K. Kono, H. Hayashi (Univ. of
Miyazaki),
S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:


The long GRB 090410 (Swift/BATtrigger #348929 ; Grupe et al.,
GCN 9122) triggered the Suzaku Wide-band  All-sky Monitor (WAM)
 which covers an energy range of 50 keV - 5 MeV at 16:57:53.392 UT
(=T0).

The observed light curve shows  main peaks starting at T0-5s, ending
at T0+25s, followed by a long weak tail seen up to T0+150s. And the
precursor activity reported by Swift/BAT (Barthelmy et al., GCN 9123)
is also seen at T0-55s. The total T90 duration including this precursor
is about 166 seconds. The fluence in 100 - 1000 keV was 1.2 +/- 0.3  x
10^-5 erg/cm^2. The 1-s scaled peak flux measured from T0+5s was 3.0
(-0.3, +0.2)
photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-60s to
T0+150s is well fitted by a single power-law with a photon index
of 2.3 (-0.3, +0.3) (chi^2/d.o.f = 4.9/8), and the spectrum of the main
bright peak from T0-5s to T0+25s is well fitted by a power-law with
exponential cutoff model:
 dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
 alpha       1.3 +/-0.5, and
 Epeak       304 (-79, +60) keV (chi^2/d.o.f. = 7.9/7).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:

 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090411A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9130
SUBJECT: GRB 090411A: Fermi GBM detection
DATE:    09/04/16 14:36:53 GMT
FROM:    Rob Preece at UAH  <Rob.Preece@nasa.gov>

Rob Preece (UAH)reports on behalf of the Fermi GBM Team:

"At 20:06:36.89 UT on 4 April, 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090411 (trigger 261173198 / 090411838).

The on-ground calculated location, using the GBM trigger
data, is RA = 159.34, DEC = -68.36 (J2000 degrees,
equivalent to 10 h 37 m, 68 d 21'), with an uncertainty
of 2.3 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 59 degrees.

The GBM light curve consists of two main pulses
with a duration (T90) of about 24.6 s (8-1000 keV).
The time-averaged spectrum from T0-2.04 s to T0+18.4 s is
best fit by a Band function with Epeak = 141 +/- 35 keV,
alpha = -0.88 +/- 0.15, and beta = -1.82 +/- 0.08
(chi squared 319.93 for 318 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(8.6 +/- 1.2)E-6 erg/cm^2. The 0.256-sec peak photon flux measured
starting from T0+11.75 s in the 8-1000 keV band
is 3.25 +/- 0.94 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090411B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9131
SUBJECT: GRB 090411B: Fermi GBM detection
DATE:    09/04/16 14:39:32 GMT
FROM:    Rob Preece at UAH  <Rob.Preece@nasa.gov>

Rob Preece (UAH) reports on behalf of the Fermi GBM Team:

"At 23:47:44.88 UT on 11 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090411B (trigger 261186466 / 090411991).

The on-ground calculated location, using the GBM trigger
data, is RA = 37.0, DEC = 3.2 (J2000 degrees,
equivalent to 02 h 28 m, 3 d 15 '), with an uncertainty
of 2.8 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 111 degrees.

The GBM light curve consists of a single spiky outburst
with a duration (T90) of about 18.7 s (8-1000 keV).
The time-averaged spectrum from T0-2.56 s to T0+20.9 s is
adequately fit by a Band function with Epeak = 189 +/- 37 keV,
alpha = -0.8 +/- 0.1, and beta = -2.0 +/- 0.2
(chi squared 369 for 325 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(8.0 +/- 0.8)E-6 erg/cm^2. The 0.256-sec peak photon flux measured
starting from T0+6.15 s in the 8-1000 keV band
is 7.4 +/- 3.0 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090412A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9132
SUBJECT: GRB 090412: Fermi GBM detection
DATE:    09/04/16 17:49:35 GMT
FROM:    Rob Preece at UAH  <Rob.Preece@nasa.gov>

Rob Preece (UAH) reports on behalf of the Fermi GBM Team:

"At 01:28:05.25 UT on 12 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located a weak GRB 090412 (trigger 261192487 / 090412061).

The on-ground calculated location, using the GBM trigger
data, is RA = 0.3, DEC = -49.8 (J2000 degrees,
equivalent to 00 h 01 m, -48 d 48 '), with an uncertainty
of 9.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 71 degrees.

The GBM light curve consists of a weak pulse
with a duration (T90) of about 0.5 s (8-1000 keV).

Since the source is very weak, it is not possible to
perform any spectral analysis."


GRB_name: GRB090417A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9133
SUBJECT: GRB 090417: Swift detection of a short burst
DATE:    09/04/17 13:37:57 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (MSSL),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), M. Perri (ASDC), P. Romano (INAF-IASFPA),
B. A. Rowlinson (U Leicester), B. Sbarufatti (INAF-IASFPA),
M. C. Stroh (PSU), T. N. Ukwatta (GSFC/GWU), L. Vetere (PSU) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:

At 13:17:23 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090417 (trigger=349447).  Swift did not slew immediately
due to a Sun constraint. 
The BAT on-board calculated location is 
RA, Dec 34.995, -7.181 which is 
   RA(J2000) = 02h 19m 59s
   Dec(J2000) = -07d 10' 51"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 0.1 sec.  The peak count rate
was ~3200 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift cannot slew to the BAT position. 
There will thus be no XRT or UVOT data for this trigger.  This location
will not come out of constraint until 02 Jun 2009. 

Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090417A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9134
SUBJECT: GRB 090417:  2MASS galaxy within BAT Localization
DATE:    09/04/17 14:11:21 GMT
FROM:    Derek Fox at PSU  <dfox@astro.psu.edu>

D. B. Fox (Penn State) reports:

"I note the presence of a bright (J_tot=13.4 mag) galaxy, 2MASX
J02194771-0712008, within the BAT localization region of the
Swift-detected short burst GRB 090417 (Mangano et al., GCN 9133).
Considering the average sky density of 2MASS extended source catalog
objects of this magnitude or brighter, the presence of such a galaxy
within a region of 3-arcmin radius is suggestive at roughly
97%-confidence."


GRB_name: GRB090417B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9135
SUBJECT: GRB 090417B: Swift detection of a burst
DATE:    09/04/17 15:41:13 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

B. Sbarufatti (INAF-IASFPA), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), P.A. Curran (MSSL-UCL),
P. A. Evans (U Leicester), O. Godet (U Leicester),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (MSSL),
V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB),
R. Margutti (Univ Bicocca&OAB), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), P. Romano (INAF-IASFPA),
B. A. Rowlinson (U Leicester), M. H. Siegel (PSU),
M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 15:20:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090417B (trigger=349450).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 209.706, +47.000 which is 
   RA(J2000)  =  13h 58m 49s
   Dec(J2000) = +47d 00' 01"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The TDRSS BAT light does not show much 
for this 320-sec image trigger (as is typical for image triggers). 

The XRT began observing the field at 15:26:30.4 UT, 387.0 seconds after
the BAT trigger. XRT found a bright, uncatalogued and fading X-ray source 
located at RA, Dec 209.6931, +47.0170 which is equivalent to:
   RA(J2000)  = 13h 58m 46.34s
   Dec(J2000) = +47d 01' 01.2"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 68 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

The initial flux in the 2.5 s image was 2.77e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 395 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The 3-sigma upper limit is white = 20.1 mag. 
No correction has been made for the expected extinction corresponding to E(B-V) 
of 0.02. 

Burst Advocate for this burst is B. Sbarufatti (sbarufatti AT ifc.inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090417A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9136
SUBJECT: GRB 090417A: nearby galaxy redshift 
DATE:    09/04/17 16:27:39 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

P. T. O'Brien and N. R. Tanvir (U. Leicester) report:

We note that the bright 2MASS galaxy at the edge of the BAT error
circle, pointed out by Fox (GCN 9134), has a spectrum measured as part
of the 6dF survey, which gives a redshift of z=0.088.  This
corresponds to a luminosity distance of about 400 Mpc in standard
cosmology, which would be very large for an SGR giant flare, but quite
plausible for a short-GRB comparable in luminosity to several others
which have been seen at moderate redshifts.

The spectrum can be seen at the following link:
http://www-wfau.roe.ac.uk/6dFGS/cgi-bin/show.cgi?release=dr3&name=g0219477-071201&tid=-1&specid=123101


GRB_name: GRB090417A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9137
SUBJECT: GRB 090417A: Early-type nature of the putative host
DATE:    09/04/17 17:35:29 GMT
FROM:    Josh Bloom at UC Berkeley  <jbloom@astron.berkeley.edu>

J. S. Bloom (UC Berkeley), D. Fox (PSU), N. R. Tanvir, P. T. O'Brien  
(U. Leicester), William Lee (UNAM), J. X. Prochaska (UCO/Lick) report:

We further note that the galaxy possibly associated (Fox GCN 9134)  
with GRB 090417A (Mangano et al., GCN 9133) appears both visually and  
spectrally to be of an early-type (smooth morphology, prominent Ca  
H&K). In the 6df spectrum (O'Brien & Tanvir, GCN 9136), there is some  
low-level HÎ± emission apparent suggesting some low-level star- 
formation. However no other Balmer lines appear prominently detected  
and there is no apparent [OIII] or [OII] as seen in the host galaxies  
of essentially all long-soft GRB (LSB) hosts. Without a detailed  
analysis, we classify this galaxy as a S0/lenticular or (more likely)  
an elliptical. Given the connection of several other SHBs to  
ellipticals at moderate redshift, we feel this identification can be  
taken as weak observational support for a connection between this  
galaxy and 090417A and further suggests that the burst was unlikely to  
be due to an SGR flare-type event (O'Brien & Tanvir, GCN 9136). The  
fact that the galaxy is at the edge of the BAT error circle does not  
necessarily argue against it being the host: the offset from the  
center of the circle, which amounts  to ~320 kpc at this redshift, is  
certainly within the range of plausible natal kicks of a compact  
binary progenitor (~1 Gyr merger time for a 500 km/s kick).


GRB_name: GRB090417A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9138
SUBJECT: GRB 090417A: Swift-BAT refined analysis
DATE:    09/04/17 19:50:47 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-119 to T+261 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090417A (trigger #349447)
(Mangano, et al., GCN Circ. 9133).  The BAT ground-calculated position is
RA, Dec = 34.993, -7.141 deg which is 
   RA(J2000)  =  02h 19m 58.3s 
   Dec(J2000) = -07d 08' 28.9" 
with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 30%.
 
The mask-weighted light curve shows a single peak starting at T-0.06 sec,
peaking at T+0.04 sec, and ending at T+0.09 sec.  There appears to be
no extended emmission out to T+55 sec, at which point the burst location
went out of the BAT FOV during a planned target slew.  T90 (15-350 keV)
is 0.072 +- 0.018 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.0 to T+0.1 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index -0.65 +- 2.11, 
and Epeak of 40.3 +- 12.7 keV (chi squared 67.41 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.9 +- 0.5 x 10^-8 erg/cm2
and the 1-sec peak flux measured from T-0.46 sec in the 15-150 keV band is
3.6 +- 1.0 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.99 +- 0.36 (chi squared 77.85 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/349447/BA/


GRB_name: GRB090417B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9139
SUBJECT: GRB 090417B: Swift-BAT refined analysis
DATE:    09/04/17 23:31:58 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090417B (trigger #349450)
(Sbarufatti, et al., GCN Circ. 9135).  The BAT ground-calculated position is
RA, Dec = 209.624, 46.954 deg, which is 
   RA(J2000)  =  13h 58m 29.7s 
   Dec(J2000) = +46d 57' 14.1" 
with an uncertainty of 4.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 94%.
 
The mask-weighted light curve shows that this burst started before T-200 sec
(where we start collecting event data on each trigger), slowly rises
to a peak around T+400 sec and slowly decreases out past T+950 sec
(where we stop processing the data).  T90 (15-350 keV) is greater than 260 sec.
 
The time-averaged spectrum from T+278.7 to T+617.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.85 +- 0.14.  The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+434.93 sec in the 15-150 keV band
is 0.3 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/349450/BA/


GRB_name: GRB090417B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9140
SUBJECT: GRB090417B: optical observations
DATE:    09/04/18 00:23:39 GMT
FROM:    Johan U. Fynbo at U.Copenhagen  <jfynbo@astro.ku.dk>

J. P. U. Fynbo, D. Malesani, Jens Hjorth (DARK/NBI), E. Leitet, Staffan
Linne (Uppsala), Thomas A. Ottosen (NOT), P. Jakobsson (Univ. Iceland),
report on behalf of a larger collaboration:

We observed the field of GRB 090417B (Sbarufatti et al., GCN 9135) with
the NOT equipped with ALFOSC. Observations were carried out in the B, R
and i bands.

Inside the revised XRT error circle, we find a single source detected in
all three bands, with approximate magnitude R=21.3 (at mean time Apr
17.966, 7.84 hr after the GRB).

The source is also visible in the SDSS and classified as a galaxy.
Photometry reveals that the object has approximately the same brightness
as in the SDSS (in the R band). In the NOT images the object also appears
extended. The source is thus unlikely to be the afterglow of GRB 090417B,
although it may be its host galaxy.

We acknowledge excellent support from the NOT staff and observer.


GRB_name: GRB090417B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9141
SUBJECT: GRB 090417B: optical observations
DATE:    09/04/18 01:25:33 GMT
FROM:    Igor Volkov at Asro.Inst.Slovak Acad.Sciences  <volkov@ta3.sk>

On 2009 April 17  I observed the field of GRB 090417B (Sbarufatti et al.
GCN Circ. 9135) with the 0.5m reflector and ST-10XME CCD camera of Stara
Lesna (Slovak Republic) observatory. I have got 11 frames in standard Rc
system, starting at 22:10:05 UT, 23332s after the alert. In my coadded
frame (total exposition 930s)it was not possible to detect a single source
inside the refined XRT error box (Sbarufatti et al. GCN Circ. 9135) with
S/N rate more than 5, which corresponds to limiting magnitude Rc >19.9.
The time of the middle of the sequence was 22:18:00 UT. GSC2.3 catalog was
used for flux calibration.

Igor Volkov, visiting astronomer of Astronomical Institute of the Slovak
Academy of Sciences, 059 60 Tatranska Lomnica, Slovak Republic; Sternberg
Astronomical Institute, 119992  Moscow, Universitetskij pr.13;
e-mail: volkov@ta3.sk, imv@sai.msu.ru


GRB_name: GRB090417B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9142
SUBJECT: GRB090417B: Xinglong TNT optical upper limit
DATE:    09/04/18 05:03:56 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L. P. Xin, X. F. Wang, W. K. Zheng, Y. L. Qiu, J. Y. Wei,
J. Wang, J. S. Deng, Y. Urata and J. Y. Hu
on behalf of EAFON report:

We have observed GRB 090417B (Sbarufatti et al., GCN 9135)
with Xinglong TNT telescope from  Apr.17,15:34:38(UT),
14.5 min after the burst. The weather was cloudy.
After combined  white and R band images, 
no new source was found in our combined images. 
The 3 sigma upper limits derived from USNO-B1.0 R2 
magnitudes were shown as following:
--------------------------------------------------------
MeanTime exposure  Band   Mag    UpperLimit?   coadded?
--------------------------------------------------------
16.5min    8*40s   white  20.1       yes          yes
1.63hr    29*300s   R     21.6       yes          yes
-------------------------------------------------------

We also notice that in the location of XRT error circle,
a extended object was likely to be present,
as found by Fynbo et al (GCN 9140).
However, the S/N is very low that we could not make sure.

This message may be cited.

For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/


GRB_name: GRB090417B
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9143
SUBJECT: GRB 090417B: MITSuME Okayama optical upper limits
DATE:    09/04/18 06:21:01 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

D. Kuroda, M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 090417B (Sbarufatti et al. GCN 9135)
with optical three color (g', Rc and Ic) CCD camera attached to
the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
We started the observation at 15:29:29 UT, 566s after the burst.
There is no point source brighter than 20 mag within the XRT error
circle (Cummings et al. GCN 9139) in our 5940 sec exposure frames.
3-sigma upper limits to our observation are listed below.
We used GSC2.3 catalog for flux calibration.

 Mid-UT      Td         EXP-T           g'     Rc     Ic
-----------------------------------------------------------
15:34:43     880s    540s (9x60s)     >19.2  >18.8  >18.4
15:44:55    1492s   1560s (24x60s)    >19.9  >19.6  >19.1
15:59:37    2374s   3000s (50x60s)    >20.2  >19.9  >19.4
16:29:42    4179s   5940s (99x60s)    >20.3  >20.0  >19.5
-----------------------------------------------------------


GRB_name: GRB090417B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9144
SUBJECT: GRB 090417B: Liverpool Telescope observations
DATE:    09/04/18 09:13:41 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), R. Smith, C.G. Mundell (Liverpool JMU),
A. Gomboc (U. Ljubljana), P. O'Brien, N. Tanvir (U. Leicester) on
behalf of a large collaboration report:

On 2009 April 18 at 03:10:50 UT we observed the Swift GRB 090417B
(Sbarufatti et al., GCN Circ. 9135) with the Liverpool Telescope
using the SDDS-R filter.

 From a 6x300 s frame, inside the revised XRT error circle we clearly
detect the SDSS galaxy already mentioned by Fynbo et al. (GCN Circ. 9140).
At a mid epoch of 12.10 hrs post burst we estimate its magnitude of
r'=21.9 +/- 0.3, calibrated with respect to nearby SDSS stars.
This value is consistent with that reported in the SDSS catalogue of
21.6 mag. We therefore conclude that this source is not the afterglow of
GRB 090417B, while it could possibly be its host galaxy, as already
suggested by Fynbo et al. (GCN Circ. 9140).


GRB_name: GRB090417B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9145
SUBJECT: GRB 090417B: Subaru NIR Observations
DATE:    09/04/18 09:53:27 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>

K. Aoki, I. Tanaka, F. Nakata (Subaru Telescope), K. Ohta, S. Yuma (Kyoto U),
and N. Kawai (Tokyo Tech) report on behalf of the Subaru GRB team:

We observed the field of GRB 090417B (Sbarufatti et al. GCN 9135)
with MOIRCS on Subaru Telescope in J band Ks bands under a
cirrus condition.
The observing period is from 05:00 UT to 07:45 UT on April 18th,
about 15 hours after the burst.
In the XRT error circle, we detected the object reported
by Fynbo et al. (GCN 9140).
Roughly estimated J and Ks magnitudes of this object relative
to a nearby 2MASS star are 20.0 mag and 18.5 mag (Vega), respectively.
The object seems to be point-like under the seeing condition of
0."7, though the S/N is not so good to be definitive.
No other sources are found in the error circle.

The GRB may be a dusty GRB in the galaxy seen in the SDSS image,
or might be a high redshift GRB that appeared far behind the galaxy,
or intrinsically very faint.


GRB_name: GRB090411A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9146
SUBJECT: GRB 090411A: Suzaku WAM observation of the prompt emission
DATE:    09/04/18 10:01:48 GMT
FROM:    Masanori Ohno at ISAS/JAXA  <ohno@astro.isas.jaxa.jp>

M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa
(RIKEN),
T. Uehara, T. Takahashi, Y. Fukazawa, Y. Hanabata (Hiroshima U.),
E. Sonoda, M. Yamauchi, N. Ohmori, K. Kono, H. Hayashi (Univ. of
Miyazaki),
S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090411A (Fermi-GBM trigger #261173198 ; Preece et al., GCN 9130)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
 energy range of 50 keV - 5 MeV at 20:06:36 UT (=T0).
The observed light curve shows a double-peaked structure starting at T0-1s,
ending at T0+20s (T90) of about 16 seconds.
The fluence in 100 - 1000 keV was 7.0 +/-0.6 x 10^-6 erg/cm^2.
The 1-s peak flux measured from T0+12s was 2.5(-0.4,+0.3)
photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+20s is well fitted by a single power-law with a photon index
of 1.9 (-0.1,+0.2) (chi^2/d.o.f = 9.2/13).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:

 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090411B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9147
SUBJECT: GRB 090411B: Suzaku WAM observation of the prompt emission
DATE:    09/04/18 10:04:13 GMT
FROM:    Masanori Ohno at ISAS/JAXA  <ohno@astro.isas.jaxa.jp>

M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa
(RIKEN),
T. Uehara, T. Takahashi, Y. Fukazawa, Y. Hanabata (Hiroshima U.),
E. Sonoda, M. Yamauchi, N. Ohmori, K. Kono, H. Hayashi (Univ. of
Miyazaki),
S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:


The long GRB 090411B (Fermi-GBM trigger #261186466/090411991;
 Preece et al., GCN 9131)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
 energy range of 50 keV - 5 MeV at 23:47:38 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0-1s,
ending at T0+25s with a duration (T90) of about 20 seconds.
The fluence in 100 - 1000 keV was 7.6 +/- 0.3 x 10^-6 erg/cm^2.
The 1-s peak flux measured from T0+6s was 2.3 +/- 0.2 photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+22s is well fitted by a single power-law with a photon index
of 2.4 +/- 0.1 (chi^2/d.o.f = 23.2/21).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:

 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9148
SUBJECT: GRB 090418 OA candidate
DATE:    09/04/18 11:16:22 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

R. Chornock, S. B. Cenko, W. Li, and A. V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:

The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory automatically
slewed to the position of GRB 090418 and discovered a new new point source not
present in the DSS at coordinates (J2000):  17:57:15.17  +33:24:21.1

at an unfiltered magnitude of approximately 15.8 at UT=11:10:57.  Further
observations are in progress.


GRB_name: GRB090418A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9149
SUBJECT: GRB 090418: Swift detection of a burst with optical afterglow
DATE:    09/04/18 11:35:24 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
P.A. Curran (MSSL-UCL), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),
J. Mao (INAF-OAB), P. T. O'Brien (U Leicester), D. M. Palmer (LANL),
A. M. Parsons (GSFC), M. Perri (ASDC), B. A. Rowlinson (U Leicester),
B. Sbarufatti (INAF-IASFPA), G. Tagliaferri (INAF-OAB),
T. N. Ukwatta (GSFC/GWU), L. Vetere (PSU) and H. Ziaeepour (UCL-MSSL)
report on behalf of the Swift Team:

At 11:07:40 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090418 (trigger=349510).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 269.334, +33.409 which is 
   RA(J2000)  =  17h 57m 20s
   Dec(J2000) = +33d 24' 31"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two main peaks
with a duration of about 70 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~45 sec after the trigger. 

The XRT began observing the field at 11:09:16.3 UT, 96.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
269.3129, 33.4055 which is equivalent to:
   RA(J2000)  = 17h 57m 15.09s
   Dec(J2000) = +33d 24' 19.9"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 64 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
3.55e+20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 1.05e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 250 seconds with the u filter starting
859 seconds after the BAT trigger. An afterglow candidate has been
found in the initial data products at
    RA(J2000) =  17:57:15.1 = 269.31458
   Dec(J2000) = +33:24:21   = +33.40583
with an estimated uncertainty of 1.0 arcsec (radius, 90% confidence, statistical
+ systematic).  This is 1.1 arcsec from the XRT position.  The estimated 
magnitude is u = 17.3 mag. No correction has been made for the expected 
extinction corresponding to E(B-V) of 0.04. 

Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9150
SUBJECT: GRB 090418: ROTSE-III Confirmation of Optical Counterpart
DATE:    09/04/18 12:10:59 GMT
FROM:    Fang Yuan at ROTSE  <yuanfang@umich.edu>

F. Yuan (U Mich), B. E. Schaefer (Louisiana State), W. Rujopakarn  
(Steward), report on behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB  
090418 (Swift trigger 349510; Mangano et al, GCN 9149) in twilight.  
The first image was at 11:07:59.2 UT, 19.0 s after the burst (4.2 s  
after the GCN notice time). The unfiltered images are calibrated  
relative to USNO B1.0.
We detect the optical counterpart at the KAIT and UVOT position  
(Chornock et al. GCN 9148;  Mangano et al, GCN 9149) at the following  
magnitude and limit:

start UT         end UT       mag      magerr    mlim(of image)
--------------------------------------------------------------------------------
11:07:59.2     11:09:06.3     15.9       0.1         17.0
11:09:19.6     11:14:02.1     15.9       0.1         16.8
11:14:11.3     11:25:31.5      -             -             16.7


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9151
SUBJECT: GRB 090418 Lick Redshift
DATE:    09/04/18 12:34:39 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

R. Chornock, S. B. Cenko, C. V. Griffith, M. E. Kislak, I. K. W. Kleiser, and
A. V. Filippenko (UC Berkeley) report:

We obtained optical spectra of the afterglow of GRB 090418 (Chornock et al., GCN
9148; Mangano et al., GCN 9149; Yuan et al., GCN 9150) using the Kast
spectrograph on the Lick 3-meter telescope.  Our first 900s exposure, starting
at 11:21:16 UT (only 816s after the burst trigger) reveals a smooth continuum
extending to the blue limit of our spectra (3450 Angs).  Superposed on the
continuum are absorption lines of C IV, Mg II, Fe II, Al II, and Mg I at
z=1.608, which we suggest is the redshift of this burst.  Further analysis is
ongoing.


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9152
SUBJECT: GRB 090418: PAIRITEL NIR detection
DATE:    09/04/18 14:13:00 GMT
FROM:    Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>

B. E. Cobb and J. S. Bloom (UC Berkeley) report:

We observed the optical afterglow of GRB 090418 (Mangano et al., GCN 9149)
with the 1.3-m Peters Automated Infrared Imaging Telescope (PAIRITEL)
beginning at 2009-04-18 11:34 UT, 26 minutes after the Swift
Trigger.  We detect the afterglow (Chornock et al., GCN 9148;  Yuan et al.,
GCN 9150) in 651 sec mosaics of 7.8 sec simultaneous individual exposures
in the J, H, and Ks filters.  Preliminary photometry for the afterglow in
these
mosaics, with midtime 2009-04-18 11:43 UT (35 minutes post-burst), yields
J = 17.7 +- 0.4, H = 17.5 +- 0.4, and  Ks = 16.1 +- 0.4
(all magnitudes given in the Vega system), calibrated to the 2MASS system.


GRB_name: GRB090417B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9153
SUBJECT: GRB 090417B: Swift-BAT further refined analysis
DATE:    09/04/18 15:31:19 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-IASFPA)
(for the Swift-BAT team):
 
Continuing the analysis for BAT GRB 090417B (trigger #349450)
(Cummings, GCN Circ 9139) using more downlinked data, we report that
this burst is very long.  The revised mask-weighted light curve
starts before T-200 sec (where we start collecting event data
on each trigger), slowly rises to a peak around T+400 sec
and slowly decreases to a minumum around T+1100 sec, then increases
to a second maximum around T+1650 sec, and then decreases again
with continuing emission past T+2100 sec (where the data stops).
The amplitudes of the two peaks are 0.09 +- 0.01 and 0.060 +- 0.006
ph/cm2/sec, resp.


GRB_name: GRB090418A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9154
SUBJECT: GRB 090418: Enhanced Swift-XRT position
DATE:    09/04/18 16:00:43 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2594 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 090418, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 269.31329, +33.40607 which is equivalent
to:

RA (J2000): 17h 57m 15.19s
Dec (J2000): +33d 24' 21.8"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090417B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9155
SUBJECT: GRB 090417B: Swift-XRT refined analysis
DATE:    09/04/18 16:55:25 GMT
FROM:    Boris Sbarufatti at INAF-IASF-Pa  <sbarufatti@ifc.inaf.it>

Sbarufatti B., Mangano V. (INAF-IASFPA) report on behalf of the
Swift Team:

We have analysed the first six orbits of Swift-XRT data obtained from
GRB 090417B (trigger 349450; Sbarufatti, et al., GCN Circ. 9135),
comprising 1456 s taken in Windowed Timing (WT) mode, from T+393 s to
T+2.0 ks,  and a total exposure of 9.2 ks in Photon Counting (PC)
mode divided in 192 s from T+1.1 ks to T+1.3 ks and 9.0 ks from
T+5.4 ks to the end of the observation at T+30 ks.

Using 6972 s of XRT Photon Counting mode data and 9 UVOT images, we
find an astrometrically corrected X-ray position (using the XRT-UVOT
alignment and matching to the USNO-B1 catalogue):
RA, Dec = 209.6942, 47.0182 which is equivalent to:

RA (J2000): 13 58 46.62
Dec (J2000): +47 01 05.4

with an uncertainty of 1.4 arcsec (90% confidence). This position
lies 4.8 arcmin from the BAT refined position, outside the quoted
error circle (Cummings, et al., GCN circ. 9139).

The 0.3-10 keV X-ray light curve of the first orbit is dominated by
flaring activity, with 3 major peaks at ~T+530, ~T+1410 s and
~T+1560 s respectively. From the second orbit on the light-curve is
decaying according to a power-law with slope -1.21+/-0.05. If
decaying at this rate, the afterglow will reach a count-rate of
1.98E-2 counts/s at T+48h.

The average WT spectrum of the first orbit is best fitted by an
absorbed power-law model with a high energy cutoff. The best fit
parameters are photon index 0.40+/-0.17, cutoff energy 3.1+/-0.4 keV
and NH (9.2+/-0.6)E21 cm^-2, in large excess with respect to the
galactic value 1.6E20 cm^-2 (Kalberla et al. 2005). The average
observed(unabsorbed) flux in the 0.3-10 keV band is 1.6(2.1)E-9 ergs
cm^-2 s^-1. The average spectrum of the large double peaked flare
between T+1.3 ks and T+2.0 ks is also fitted by an absorbed power-law
model with a high energy cutoff with best fit parameters photon
index 0.46+/-0.2, cutoff energy 3.2+/-0.5 and NH (9.5+/-0.7)E21 cm^-2.
The average PC spectrum in the T+5.4 ks - T+30 ks interval is well
fitted by an absorbed power-law with photon index 2.0+/-0.1 and NH
(9.6+/-0.10E21 cm^-2. The average  observed(unabsorbed) flux in the
0.3-10 keV band is 2.8(5.6)E-11 ergs cm^-2 s^-1.
The count-rate to flux conversion factor is 1.0E-10.
All quoted errors are at 90% confidence level.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00349450.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090417B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9156
SUBJECT: GRB 090417B:  Galaxy redshift
DATE:    09/04/18 17:49:52 GMT
FROM:    Edo Berger at Harvard  <eberger@cfa.harvard.edu>

E. Berger (Harvard) and D.B. Fox (PSU) report:

"We obtained spectroscopic observations of the SDSS galaxy located inside
the XRT error circle of GRB 090417B (GCNs 9153, 9155, 9140) with GMOS on
the Gemini-North telescope.  In a combined 1800 sec spectrum we detect
emission lines corresponding to [OII]3727, [OIII]5006, and H-alpha at a
redshift of z=0.345.  At this redshift the observed fluence of the burst
(2.3e-6 erg/cm^2; GCN 9139) translates to an isotropic-equivalent energy
of 9e50 erg."


GRB_name: GRB090418A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9157
SUBJECT: GRB 090418: Swift-BAT refined analysis
DATE:    09/04/18 17:54:33 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

E. E. Fenimore (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), V. Mangano (INAF-IASFPA), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+705 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090418 (trigger #349510)
(Mangano, et al., GCN Circ. 9149).  The BAT ground-calculated position is
RA, Dec = 269.320, 33.407 deg, which is 
   RA(J2000)  =  17h 57m 16.8s 
   Dec(J2000) = +33d 24' 24.4" 
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.
 
The mask-weighted light curve shows two clusters of peaks.  The first
starts at ~T-8 sec, peaks at ~T+1 sec, and reaches a minimum at T+15 sec.
The second cluster peaks at around T+40 sec and returns to background
at ~T+70 sec.  T90 (15-350 keV) is 56 +- 5 sec (estimated error
including systematics).
 
The time-averaged spectrum from T-8.5 to T+61.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.48 +- 0.07.  The fluence in the 15-150 keV band is 4.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.06 sec in the 15-150 keV band
is 1.9 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/349510/BA/


GRB_name: GRB090417B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9158
SUBJECT: GRB 090417B: Gemini imaging
DATE:    09/04/18 18:54:50 GMT
FROM:    Edo Berger at Harvard  <eberger@cfa.harvard.edu>

E. Berger (Harvard), D.B. Fox (PSU), and N. Tanvir (Leicester) report:

"In addition to the spectroscopic observations described in GCN 9156, we
also imaged the field of GRB 090417B with GMOS in the griz filters
starting on 2008 April 18.38 (17.7 hours after the burst).  A total of 360
sec were obtained in gri, and a total of 540 sec was obtained in z.  We
find the following magnitudes for the SDSS galaxy coincident with the XRT
afterglow position:

g = 22.47+/-0.16 mag (SDSS: 23.0+/-0.5 mag)
r = 21.62+/-0.10 mag (SDSS: 21.62+/-0.16 mag)
i = 21.31+/-0.12 mag (SDSS: 21.41+/-0.09 mag)
z = 21.49+/-0.30 mag (SDSS: 20.78+/-0.25 mag)

Thus, we find no evidence for brightening compared to the SDSS archival
magnitudes."


GRB_name: GRB090418B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9159
SUBJECT: GRB 090418B: Detection of a bright burst from Swift-BAT slew data
DATE:    09/04/18 22:19:33 GMT
FROM:    Antonio Copete at Harvard U  <acopete@head.cfa.harvard.edu>

A. Copete, J. Grindlay (Harvard)
S. Barthelmy, C. Markwardt, N. Gehrels (NASA/GSFC)

We report the detection of a bright GRB by the BAT Slew Survey (BATSS)  
in the slew that started at 08:59:02 and lasted 151 sec. The ground- 
calculated position is RA, Dec = 225.910, +17.224 deg, which is
RA (J2000) = 15h 03m 38s
Dec(J2000) = +17d 13' 26"
with an uncertainty of 1.91 arcmin (90% confidence, including  
systematics). The detection was triggered by simultaneous independent  
detections of 86.0 sigma and 41.8 sigma from imaging in the 15-50 keV  
and 50-150 keV energy bands, respectively. The burst mask-tagged  
lightcurve lightcurve in the 15-150 keV band shows a strong and broad  
multi-peaked emission structure starting at T+25sec as the burst  
enters the BAT field-of-view, lasting 48 sec, and peaking 6 times at T 
+29, T+35, T+38, T+47, T+58 and T+62sec. This is followed by a weaker  
broad peak starting at T+87sec, lasting 28sec and peaking at T+100sec.  
T90 = 65.0sec and T50 = 17.0sec.

The time-averaged spectrum over the 120 sec exposure time of the  
source is best fit by a power law with an exponential cutoff, with  
photon index 1.42 and high-energy cut at 319 keV. The fluence in the  
15-150 keV band is 1.6 x 10^-5 erg/cm^2, and the peak 1-sec flux is  
6.5 x 10^-7 erg/cm^2/sec at T+38sec. A follow-up Swift ToO observation  
for this burst has been scheduled.


GRB_name: GRB090417A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9160
SUBJECT: VLA observations of short burst GRB 090417A
DATE:    09/04/19 13:23:35 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

P. Chandra (RMC) and D. A. Frail (NRAO) report on behalf of a larger
collaboration:

"We have used the Very Large Array (VLA) to image a field centered on
the 2MASS galaxy suggested by Fox (GCN #9134) to be a possible host of
the short duration burst 090417A (GCN # 9133, 9138). The VLA observed
the burst at a frequency of 8.46 GHz on two epochs, April 17.92 UT and
April 18.90 UT. Within a radius of 1.5 arcmin around the 2MASS galaxy
there are no radio sources detected at either epoch to a 4-sigma limit
of 104 uJy and 84 uJy, respectively. No further observations are planned.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090419A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9161
SUBJECT: GRB 090419: Swift detection of a burst
DATE:    09/04/19 13:59:53 GMT
FROM:    David Burrows at PSU/Swift  <dxb15@psu.edu>

G. Stratta (ASDC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), N. P. M. Kuin (MSSL),
V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB),
R. Margutti (Univ Bicocca&OAB), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), A. M. Parsons (GSFC), M. Perri (ASDC),
P. Romano (INAF-IASFPA) and B. Sbarufatti (INAF-IASFPA) report on
behalf of the Swift Team:

At 13:43:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090419 (trigger=349592).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 196.976, -75.609 which is 
   RA(J2000) = 13h 07m 54s
   Dec(J2000) = -75d 36' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a slow single
peak taking 30 seconds to rise to a maximum with a duration of
at least 90 seconds, and an additional peak at T+320.  The peak
count rate was ~800 counts/sec  (15-350 keV), at ~30 sec after 
the trigger. 

The XRT began observing the field at 13:45:31.0 UT, 119.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 196.92907,
-75.60534 which is equivalent to:
   RA(J2000)  = 13h 07m 42.98s
   Dec(J2000) = -75d 36' 19.2"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 44 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.2e+21
cm^-2, Kalberla et al. 2005), with an excess column of 1.1
(+0.85/-0.64) x 10^22 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 5.55e-10 erg cm^-2 s^-1 (0.2-10
keV). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 126 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The coverage of the XRT error circle by the 8'x8' region for the list of
sources generated on-board is uncertain because the large number of sources
filled the available telemetry. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.30. 




Burst Advocate for this burst is G. Stratta (giulia.stratta AT asdc.asi.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9162
SUBJECT: GRB 090418A: ROTSE-III Refined Analysis
DATE:    09/04/19 16:15:56 GMT
FROM:    Fang Yuan at ROTSE  <yuanfang@umich.edu>

F. Yuan (U Mich) report on behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB  
090418A (Swift trigger 349510; Mangano et al, GCN 9149) 19.0 s after  
the burst, during the gamma-ray emission, and detected the optical  
counterpart (Yuan et al, GCN 9150). We took 10 5-sec, 10 20-sec and 26  
60-sec useful exposures before sunrise. Further analysis of single  
images revealed an initially rising lightcurve with two subsequent  
peaks at ~40s (~15.6 mag) and ~130s (~15.4 mag) before the OT dropped  
below our detection limit.


GRB_name: GRB090418A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9163
SUBJECT: GRB 090418: Swift XRT refined analysis
DATE:    09/04/19 16:55:19 GMT
FROM:    Vanessa Mangano at INAF-IASFPA  <vanessa@ifc.inaf.it>

Mangano V., Sbarufatti B. (INAF-IASFPA) report on behalf of the
Swift XRT Team:

We have analysed the first four orbits of Swift-XRT data obtained from
GRB 090418 (trigger 349510; Mangano, et al., GCN Circ. 9149),
comprising 116 s taken in Windowed Timing (WT) mode, from T+102 s to
T+218 s, and a total exposure of 8.5 ks in Photon Counting (PC)
mode from T+219 s to the end of the observation at T+18 ks.

The best position of the X-ray afterglow is the UVOT enhanced XRT
position given in Goad, et al., GCN Circ. 9154, that is
RA, Dec = 269.31329, +33.40607 which is equivalent to:

RA (J2000): 17h 57m 15.19s
Dec (J2000): +33d 24' 21.8"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

The 0.3-10 keV X-ray light curve is well fitted by a doubly broken
pawer law, with a initial decay slope alpha1=1.7+/-0.1,
a first breal at about T+245 s, an intermediate decay slope
alpha2=0.35 -0.1+0.06, a second break at about T+2 ks and
a final decay slope alpha3=1.39+/-0.06
If decaying at this rate, the afterglow will reach a count-rate of
6.1E-3 counts/s at T+48h.

The average WT spectrum (corresponding to the initial steep decay phase)
is best fitted by an absorbed power-law model, with photon index 2.0+/-0.2,
and intrinsic NH=(6+/-3)E21 cm-2 (at the redshift z=1.608,
Chornock, et al., GCN circ. 9151) in excess with respect to the galactic
absorption value of 3.6E20 cm-2 (Kalberla et al. 2005).
The average observed(unabsorbed) flux in the 0.3-10 keV band is
3.5(4.6)E-10 ergs cm-2 s-1.
The average PC spectrum of the first orbit (covering the intermediate
slowly decaying phase) is well fitted by an absorbed power-law model,
with photon index 2.1+/-0.1, intrinsic NH=(1.2+/0.3)E22 cm-2
and average observed(unabsorbed) flux in the 0.3-10 keV band of
1.5(2.2)E-10 ergs cm-2 s-1.
Finally, the average PC spectrum from T+4.2 ks to T+18 ks (orbits 2-4)
is well fitted by an absorbed power-law model,
with photon index 2.0+/-0.1, intrinsic NH=(1.1+/0.2)E22 cm-2
and average observed(unabsorbed) flux in the 0.3-10 keV band of
1.3(1.8)E-11 ergs cm-2 s-1.
The average count-rate to observed(unabsorbed) flux conversion factor
is 4.5(6.5)E-11.
All quoted errors are at 90% confidence level.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00349510.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090419A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9164
SUBJECT: GRB 090419: Enhanced Swift-XRT position
DATE:    09/04/19 16:59:55 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1541 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090419, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 196.92894, -75.60586 which is equivalent
to:

RA (J2000): 13h 07m 42.95s
Dec (J2000): -75d 36' 21.1"

with an uncertainty of 1.8 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090417B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9165
SUBJECT: VLA radio upper limit on GRB 090417B
DATE:    09/04/19 23:26:11 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on
behalf of a larger collaboration:

"We used the Very Large Array to observe the field of view toward
GRB 090417B (GCN 9135) at a frequency of 8.46 GHz on 2009 Apr. 19.37
UT. The GRB radio afterglow is undetected within the Swift-XRt error
circle (GCN 9155). We place the three-sigma upper limit of 120 uJy on
the GRB afterglow.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9166
SUBJECT: VLA radio detection of GRB 090418
DATE:    09/04/19 23:59:16 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on
behalf of a larger collaboration:

"We used the Very Large Array to observe the field of view toward the
GRB 090418 (GCN 9149) at a frequency of 8.46 GHz on 2009 Apr.19.46 UT.
We observed the radio afterglow of the GRB at a position J2000
RA 17:57:15.156, Dec 33:24:20.78 which is 0.39" away from the KAIT
optical afterglow position reported by Chornock et al. (GCN 9148).
The GRB radio afterglow flux density is 219+/-44 uJy.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090419A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9167
SUBJECT: GRB 090419: Swift-BAT refined analysis
DATE:    09/04/20 01:33:40 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
G. Stratta (ASDC), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+704 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090419 (trigger #349592)
(Stratta, et al., GCN Circ. 9161).  The BAT ground-calculated position is
RA, Dec = 197.006, -75.615 deg, which is 
   RA(J2000)  =  13h 08m 01.5s 
   Dec(J2000) = -75d 36' 55.6" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.
 
The mask-weighted light curve shows a long burst with multiple peaks.
The first peak starts at ~T-30 sec.  There are comparably bright peaks
at T+50, 100, and 320 sec.  There is continued emmission out to at least T+1000 sec
and possibly T+1800 sec.  T90 (15-350 keV) is 450 +- 50 sec (estimated error
including systematics).
 
The time-averaged spectrum from T+8.1 to T+522.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.38 +- 0.16.  The fluence in the 15-150 keV band is 2.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+37.18 sec in the 15-150 keV band
is 0.4 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/349592/BA/


GRB_name: GRB090418A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9168
SUBJECT: GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
DATE:    09/04/20 07:23:37 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

D. Kuroda, M. Yoshida, M. Isogai, K. Yanagisawa, Y. Shimizu,
S. Nagayama, H. Toda, M. Isogai (NAOJ) and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 090417B (Mangano et al. GCN 9149)
with optical three color (g', Rc and Ic) CCD cameras attached to
the MITSuME 50cm telescope of Okayama Astrophysical Observatory
and the 1m telescope of Ishigaki-Jima Observatory.

We started the observation at 13:26:42 UT, 8342s after the burst
at Okayama. We could not find a new source at the position of the
afterglow (Chornock et al. GCN 9148; Mangano et al. GCN 9149;
Goad et al. GCN 9154). 3-sigma upper limits to our observations
are the following. We used GSC2.3 catalog for flux calibration.

Okayama MITSuME observation
 Mid-UT     Td(day)         EXP-T          g'     Rc     Ic
-------------------------------------------------------------
13:56:41    0.11736    2940s (49x60s)     >19.2  >19.1  >19.0
16:27:25    0.22204    5880s (98x60s)     >20.5  >20.3  >20.1
-------------------------------------------------------------

Ishigaki-Jima 1m telescope observation
 Mid-UT     Td(day)         EXP-T          g'     Rc     Ic
-------------------------------------------------------------
14:48:36    0.15342    3000s (10x300s)    >20.6  >20.9  >19.9
-------------------------------------------------------------


GRB_name: GRB090419A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9169
SUBJECT: GRB 090419: GROND detection of afterglow candidate
DATE:    09/04/20 08:28:04 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

P. Afonso (MPE Garching), S. Klose (Tautenburg) T. Kruehler and J.Greiner 
(both MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090419 (Swift trigger 349592, G. Stratta et 
al.,GCN #9161) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m 
ESO/MPI telescope at La Silla Observatory (Chile). Observations started on 
19 Apr. 2009 at 23:12 UT, 9.5 h after the burst.

Inside the enhanced XRT error circle (J.P. Osborne et al., GCN #9164) we 
detect a single faint source in the z' and J band at:

RA  (J2000) =  13:07:43.13
DEC (J2000) = -75:36:22.4

with an uncertainty of 0.5" in each coordinate.

Preliminary photometry yields the following AB magnitudes and upper limits 
in stacked images:

Filter  T_mid[h]  Exp[s]  AB Mag  MagErr
----------------------------------------
g       11.5792   12x369  >24.6
r       11.5792   12x369  >25.1
i       11.5792   12x369  24.9    0.5
z       11.5792   12x369  24.2    0.1
J       11.5859   360x10  23.0    0.2
H       11.5859   360x10  >22.1
K       11.5859   360x10  >21.2


The quoted error is statistical only. There is an additional systematic 
error in the absolute calibration using the GROND zeropoints and 2MASS 
field stars which is expected to be in the 0.2 mag range. Quoted magnitudes 
are not corrected for the significant Galactic foreground extinction 
corresponding to a reddening of E_(B-V)=0.30.

Given the lack of information about variability and the rather high density 
of foreground stars we cannot definitely associate this source with GRB 
090419 at this point. Because of the high Galactic foreground extinction, 
the upper limits in g'r' as well as the i'-z' color are not constraining, and 
the redshift is only constrained to below about 5.


GRB_name: GRB090418B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9171
SUBJECT: Konus-Wind observation of GRB 090418B
DATE:    09/04/20 13:30:41 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team report:

The long Swift-BATSS GRB 090418B (Copete et al., GCN 9159)
triggered Konus-Wind at T0=32366.325 s UT (08:59:26.325).

The burst light curve shows a soft weak precursor at ~T0-20 s, the main 
multipeaked pulse at T0 with a duration of ~45 s, and a weak soft pulse 
at ~T0+70 with a duration of ~30 s (the same lc structure was seen by 
BAT: Copete et al., GCN 9159).

As observed by Konus-Wind the burst
had a fluence of (2.31 +/- 0.09)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+15.840 s
of (1.54 +/- 0.20)x10^-6 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+40.704 s) can be fitted (in the 20 keV-1 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.23(-0.09, +0.010),
and Ep = 117(-7, +8) keV (chi2 = 62.0/56 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -3.18 (chi2 = 62.0/55 dof).

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090418_T32366/


GRB_name: GRB090419A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9172
SUBJECT: GRB 090419: Swift-XRT refined analysis
DATE:    09/04/20 15:19:33 GMT
FROM:    Matteo Perri at ISAC/ASDC  <perri@asdc.asi.it>

G. Stratta and M. Perri (ASDC) report on behalf of the
Swift-XRT Team:

We have analysed the first 4 orbits of Swift-XRT data obtained from
GRB 090419 (trigger 349592; Stratta, et al., GCN Circ. 9161),
from T+128 s to T+271 s in Windowed Timing (WT) mode and from
T+303 s to T+4.9 h in Photon Counting (PC) mode.

The best position of the X-ray afterglow is the UVOT enhanced XRT
position given in Osborne et al. (GCN Circ. 9164).

The 0.3-10 keV X-ray light curve shows an initial flaring activity
superimposed to a constant continuum at a level of ~5 counts/s
up to ~520 s after the trigger that is consistent with being
the X-ray tail of the BAT data (GCN Circ. 9167, Krimm et al.) during
the prompt emission.

Starting from 520 s up to 1200 s the count rate decays as
a power law with alpha1=3.5+/-0.5 and from T+1200
to T+12 ks it features a flattening with index alpha2=1.1+/-0.2.
If decaying at this rate, the afterglow will reach a count-rate of
1.3(0.6)E-3 counts/s at T+24(48)h.

The average WT spectrum (corresponding to the initial flat decay phase)
can be fitted by an absorbed power-law model (reduced chi square 1.0 with
18 degrees of freedom), with photon index 1.3+/-0.3, and equivalent
hydrogen column density NH=(1.1+/-0.6)E22 cm-2 in excess with
respect to the Galactic absorption value of 1.2E21 cm-2 (Kalberla et al.
2005). The average observed(unabsorbed) flux in the 0.3-10 keV band is
4.2(5.4)E-10 ergs cm-2 s-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00349510.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090417B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9173
SUBJECT: GRB 090417B Correction to the BAT refined analysis position
DATE:    09/04/20 17:04:26 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy, H. A. Krimm (GSFC/USRA),
B. Sbarufatti(INAF-IASFPA), P.A. Evans (U. Leicester)
on behalf of the Swift team

We wish to make a correction to the reported analysis of the
extremely long-duration burst GRB 090417B (GCN circ #9135,
Sbarufatti et al.).

The position in the BAT refined-analysis circular (GCN circ #9139,
Cummings et al.) was based on the results of an automated script, 
which was unable to find the optimum imaging interval due to the 
unusual length of this burst.  Thus the reported position was not 
the best BAT ground-calculated position. The best position is 
RA, Dec 209.687 +47.015, which is:

RA (J2000)    13h 58m 44.8s
Dec (J2000)   47d 00m 55s

with an error radius of ~1 arcmin. This position is 0.35 arcmin 
from the XRT refined position (GCN circ #9155, Sbarufatti et al.).

We are grateful to those who noticed the discrepancy, and regret 
any confusion resulting from this error. Any corrections to other 
BAT refined-analysis items (which are expected to be slight), such 
as to the spectral index, will appear in the final Swift Team 
report on this burst.


GRB_name: GRB090417B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9174
SUBJECT: GRB 090417B: Swift/UVOT Upper Limits
DATE:    09/04/20 19:46:26 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA) and B. Sbarufatti (INAF-IASFPA)
report on the behalf of the Swift UVOT team:

      The Swift/UVOT observed the field of GRB 090417B starting 378 s
after the BAT trigger (Sbarufatti, et al., 2009, GCN Circ. 9135).
Settled exposures started at T+395 s.  We do not find any new source,
relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT
afterglow (Sbarufatti, et al. 2009, GCN Circ. 9155).  Preliminary
3-sigma upper limits for detecting a source in the white finding
chart, and the co-added images, using a 2.5 arcsecond radius circular
aperture, are

Filter    T_start   T_stop   Exp(s)      Mag
--------------------------------------------
white (fc)    395      545      147    >21.7

v             552   13,098     1237    >21.3
b             651   19,457      862    >21.9
u            1300   25,241     1376    >22.0
uvw1          601   25,174     2300    >22.2
uvm2          750   24,268     1878    >21.8
uvw2          700   29,604     1331    >22.0
white         395     7823      841    >22.6
--------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.02 mag (Schlegel, et al., 1998, ApJS, 500,
525).  All photometry is on the UVOT photometry system described in
Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090418A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9175
SUBJECT: GRB 090418A: Swift/UVOT Observations
DATE:    09/04/20 19:47:16 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA) and V. Mangano (INAF-IASFPA) report
on the behalf of the Swift UVOT team:

        The Swift/UVOT observed the field of GRB 090418A starting 84 s
after the BAT trigger (Mangano, et al. 2009, GCN Circ. 9149).
Settled exposures started at T+160 s.  The refined UVOT position for the
optical afterglow is

       RA (J2000) =  17:57:15.17  =  269.31321 (deg)
      Dec (J2000) = +33:24:21.1   =  +33.40585 (deg)

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence,
statistical + systematic).  Preliminary 3-sigma magnitudes and upper
limits are

Filter   T_start   T_stop   Exp(s)      Mag  Err
-------------------------------------------------------------
u (fc)       160      410      246    17.31 0.09

v            466      485       19    17.31 0.24
b            415      435       19    18.22 0.25
u            539      559       19    18.55 0.39
uvw1         515      835       19   >18.1        3-sigma UL
uvm2         490      510       19   >17.6        3-sigma UL
uvw2         441      461       19   >18.1        3-sigma UL

uvw1         515   11,831     1337    20.82 0.26
          114,115  131,895     2064   >22.0        3-sigma UL
uvm2         490   18,413     2109   >21.8        3-sigma UL
uvw2         441   16,709     1357   >21.8        3-sigma UL
-------------------------------------------------------------

The quoted magnitudes have not been corrected for the expected
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.04 mag (Schlegel, et al., 1998, ApJS, 500,
525).  All photometry is on the UVOT flight system described in Poole
et al. (2008, MNRAS, 383, 627).

      The detection in the uvw1 filter, combined with the lack of a
detection in the uvm2 filter, is consistent with this source having a
redshift of z = 1.608 (Charnock, et al., 2009, GCN Circ. 9151).


GRB_name: GRB090418B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9176
SUBJECT: GRB 090418B: Faulkes Telescope North observations
DATE:    09/04/20 20:29:19 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), R.J. Smith, I.A. Steele, C.G. Mundell,
D. Bersier (Liverpool JMU), A. Gomboc (U. Ljubljana), P. O'Brien,
N. Tanvir (U. Leicester) on behalf of a large collaboration report:

On 2009 April 19 at 12:53:50 UT we observed the Swift-BAT Slew Survey
GRB 090418B (Copete et al., GCN Circ. 9159) with the 2-m Faulkes 
Telescope North using the i' and R filters.

 From a set of 6x300 s frames in each filter, we could not find any
uncatalogued object inside the BAT error circle with respect to the SDSS
field stars, down to the following limiting magnitudes:

Mid Time   Exposure  Filter   Limit
(days)      (s)               (mag)
-------------------------------------
1.17        6x300      i'      > 21
1.20        6x300      R       > 21.5
-------------------------------------


GRB_name: GRB090419A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9177
SUBJECT: GRB 090419: Swift/UVOT Observations
DATE:    09/04/20 20:31:07 GMT
FROM:    Michael Siegal at Swift/PSU  <siegel@astro.psu.edu>

M. H. Siegel (PSU), E. A. Hoversten (PSU) and G. Stratta (ASDC) report
on behalf of the Swift/UVOT team.

The Swift/UVOT began observing the field of GRB 090419 126s after the
BAT trigger (Stratta et al., GCN Circ. 9161).  Data summed over the  
first
orbit reveals a very faint (3.3 sigma) source in the white filter at the
refined position of the X-ray afterglow (Osborne et al., GCN Circ.  
9164).
This source is not detected in the second orbit data.

The detection and 3-sigma upper limits for the finding chart (fc) and
summed exposures are reported below:

FILTER     T_start(s)  T_stop     Exposure     Mag/3UL
=============================================================
white fc    126          276        147        > 20.69
white       126         1706        410          21.07+-0.31
white      5320         6956        393        > 21.25

v           614         1756        136        > 18.93
v          5732         7367        393        > 19.60

b           540         1682        116        > 19.87
b          5116        13394        572        > 20.69

u           284         1829        362        > 20.25
u          6346        13206       1081        > 20.89

uvw1        664         1805        136        > 19.31
uvw1       6142        12292       1118        > 20.63

uvm2        639         1608         58        > 18.41
uvm2       5936        17728        465        > 19.99

uvw2        590         1731        136        > 19.37
uvw2       5527         7162        393        > 20.13
=============================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.296 (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric system
described in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090418B
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9178
SUBJECT: GRB 090418B: GROND observations
DATE:    09/04/20 22:22:31 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

P. Afonso (MPE), S. Klose (Tautenburg), T. Kruehler and J. Greiner (both
MPE Garching), report on behalf of the GROND team:

GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI
telescope at La Silla Observatory (Chile) started follow-up observations of
GRB 090418B (Copete et al., GCN #9150) on April 19, at 03:00 UTC (18.0 h
after the burst). In addition, a second epoch of imaging was obtained,
which started on April 20, 04:05 UTC.

Similar to Guidorzi et al. (2009, GCN #9176) we do not detect any new object 
with respect to SDSS/2MASS inside the BAT error circle. Image subtraction 
between the two epochs does not reveal any obvious variable source. Upper 
limits from the first observation are as follows (all in the AB system):

g' > 23.8 mag
r' > 24.0 mag
i' > 23.2 mag
z' > 23.0 mag
J > 22.0 mag
H > 21.4 mag
K > 20.8 mag

Quoted upper limits have been derived using SDSS and 2MASS field stars as
reference.


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9179
SUBJECT: GRB 090418A: optical observations
DATE:    09/04/20 22:23:53 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Pavlenko, V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:

We observed the error box of  Swift GRB 090418A in   series of BVRI
exposures on Apr. 18 with Shajn telescope of CrAO.  We  detect the afterglow
(Chornock et al., GCN 9148, Mangano et al., GCN 9149) in all filters in
stacked images. Astrometry of the afterglow is RA(J2000):  17 57 15.17
Dec(J2000): +33 24 21.14 with uncertainty of 0.3 arcsec is fully compatible
with reported one in GCNs 9148, 9149.

Preliminary photometry of combined images is based on  USNO-B1.0
1234-0288651 star  RA=17:57:13.29 Dec=+33:25:00.6   is following:


T0+     Filter, Exposure, mag.,     err.
(d)             (s)
0.5484   B       36x60     23.30  +/- 0.20
0.5484   R       17x60     22.23 +/- 0.14
0.5491   I        17x60     22.40  +/- 0.24

We note, that OT is ~4" North-West of bright galaxy which is also  visible 
in POSS2.
Taking the redshift z=1.608 of the GRB source (Chornock et al., GCN  9151)
and the scale of  ~8.6 kpc/" at that redshift it is unlikely that the galaxy 
is related with OT.

A finding chart the combined image in I can be found at
http://grb.rssi.ru/GRB090418A/GRB090418_I_ZTSh_090418.gif


GRB_name: GRB090417B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9180
SUBJECT: GRB 090417B: Optical observation
DATE:    09/04/21 04:28:00 GMT
FROM:    Rupak Roy at ARIES  <rupakroy1980@gmail.com>

Brajesh Kumar, Rupak Roy, Brijesh Kumar and S. B. Pandey (ARIES, NainiTal,
India, on behalf
of larger Indian GRB collaboration).

We observed swift GRB 090417B (GCN 9135) using 104 cm Sampurnanand optical
telescope
at A.R.I.E.S. Nainital on 17th April, 2009 at 16.244 hrs UT, under good sky
conditions using
2k*2k CCD detector.

No afterglow candidate was found in our co-added R_c band image (exp time =
5*300 sec)
within the error region of BAT. Photometry of the stacked frame poses an
upper limit of
~ 21 mag, in comparison to nearby USNO-B1 stars.


GRB_name: GRB090418B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9181
SUBJECT: GRB 090418B: GRAS002 observatios
DATE:    09/04/21 06:27:00 GMT
FROM:    Veli-Pekka Hentunen at Taurus Hill Obs,A95  <veli-pekka.hentunen@kassiopeia.net>

Markku Nissinen (Taurus Hill Observatory) and Veli-Pekka Hentunen (Taurus

Hill Observatory) report:



Global-rent-a-scope GRAS002 Tak Mewlon 0.30m telescope with SBIG ST-8E

CCD at Mayhill (New Mexico, USA) was used for follow-up observations of 

GRB090418B. The observations were started on April 19, at 03:55 UTC (19 hours

after the burst) and stopped at 05:35 UTC. Four unfiltered 600 seconds images

were taken.  We do not detect any new object with respect to POSSII F/USNO-B1.0

inside the BAT error circle. Upper limit for the observations is > 20.5 mag (3UL). Quoted

upper limit has been derived using POSSII F and USNO-B1.0 field stars as reference.

 

Quoted upper limit has been derived using POSSII F and USNO-B1.0 field stars 
as reference.


GRB_name: GRB090418A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9183
SUBJECT: GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy 
DATE:    09/04/21 21:52:49 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA) reports on the behalf of the Swift
UVOT team:

      Swift/UVOT observed the POSS2 galaxy (Pavlenko, et al., 2009,
GCNC 9179) located approximately 4 arcsec northwest of the afterglow
of GRB 090418A (Mangano, et al.,2009, GCNC 9149).  We obtain the
following preliminary magnitudes and 1-sigma errors for this galaxy.

Filter  Exposure      Mag  Err  Sigma
-------------------------------------
v           6163     21.0  0.2    5.5
b           4361     22.2  0.5    2.3
u           6057     21.3  0.2    5.6
uvw1        6178     21.6  0.2    4.7
uvm2        2109     21.5  0.4    2.9
uvw2        1357     21.3  0.3    3.4
-------------------------------------

Exposure is the total exposure time in seconds.  The quoted magnitudes
have not been corrected for the expected Galactic extinction along
the line of sight corresponding to a reddening of E_{B-V} = 0.04 mag
(Schlegel, et al., 1998, ApJS, 500, 525).  All photometry is on the
UVOT photometric system described in Poole et al. (2008, MNRAS, 383,
627).

      The detection of the galaxy in the uvw2 filter suggests that the
galaxy has a redshift of less than approximately 1.3.  The redshift of
the afterglow is at least z = 1.608 (Chornock, et al., 2009, GCNC
9151).  Therefore, we conclude that this galaxy is unlikely to be the
host galaxy of GRB 090418A, in agreement with Pavlenko, et al. (2009,
GCNC 9179).


GRB_name: GRB090418C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9184
SUBJECT: GRB 090418C: Fermi GBM Detection
DATE:    09/04/22 01:08:13 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

Valerie Connaughton (UAH) reports on behalf of the Fermi GBM Team:

"At 19:35:24.92 UT on 18 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090418C (trigger 261776126 / 090418816).

The on-ground calculated location, using the GBM trigger
data, is RA = 262.8, DEC = -28.3 (J2000 degrees,
equivalent to 17 h 31 m, -28 d 18 '), with an uncertainty
of 14.4 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 58 degrees.

The GBM light curve shows a short, double-peaked burst
with a duration (T90) of about 0.6 s (8-1000 keV).
The time-averaged spectrum from T0-0.128 s to T0+0.256 s is
well fit by a power law with index -1.27 +/- 0.04, though
formally it is best fit by a power law function with an exponential
high energy cutoff.  The power law index in this case
is -0.94 +/- 0.08 and the cutoff energy, parameterized as Epeak,
lies above 1 MeV.

The event fluence (8-1000 keV) in this time interval is
(6.0 +/- 0.3)E-7 erg/cm^2. The 0.128-sec peak photon flux measured
starting from T0-0.128 s in the 8-1000 keV band
is 8.5 +/- 0.5 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090422A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9185
SUBJECT: GRB 090422: Swift detection of a burst
DATE:    09/04/22 03:51:57 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (GSFC/GWU), S. D. Barthelmy (GSFC),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), D. M. Palmer (LANL),
M. Perri (ASDC), G. Stratta (ASDC) and L. Vetere (PSU) report on
behalf of the Swift Team:

At 03:35:16 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090422 (trigger=349931).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 294.756, +40.384 which is 
   RA(J2000) = 19h 39m 01s
   Dec(J2000) = +40d 23' 03"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two spikes
with a total duration of about 10 sec.  The peak count rate
was ~3500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 03:36:20.6 UT, 64.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 294.74931,
40.38530 which is equivalent to:
   RA(J2000)  = 19h 38m 59.83s
   Dec(J2000) = +40d 23' 07.1"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 18 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.65e+21 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 5.51e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 74 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The coverage of the XRT error circle by the 8'x8' region for the list of
sources generated on-board is uncertain because the large number of sources
filled the available telemetry. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.20. 

Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090418B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9186
SUBJECT: GRB 090418B: Suzaku WAM observation of the prompt emission
DATE:    09/04/22 09:12:55 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

K. Kono, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi,
K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa
(RIKEN), 
T. Uehara, T. Takahashi, Y. Fukazawa, Y. Hanabata (Hiroshima U.),
S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090418B 
was detected by the Suzaku Wide-band  All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 08:54:21.299 UT (=T0).
The observed light curve shows a multi-peaked structure
starting at T0-3 s, ending at T0+35 s,
with a duration (T90) of about 29 seconds.

The fluence in 100 - 1000 keV was 1.22 (-0.14, +0.06) x10-5 erg/cm2.
The 1-s peak flux measured from T0+32 s was 2.13 (-0.58, +0.35) photons/cm2/s 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0+14 s to
T0+52 s is well fitted by a single power-law with a photon index
of 2.09 (-0.20, +0.22) (chi2/d.o.f = 13/17).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html


GRB_name: GRB090422A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9187
SUBJECT: GRB 090422: Liverpool Telescope observations
DATE:    09/04/22 10:19:52 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), D. Bersier, A. Melandri, C.J. Mottram,
C.G. Mundell, R.J. Smith, I.A. Steele (Liverpool JMU) on behalf of
a large collaboration report:

On 2009 April 22 at 03:37:40 UT the 2-m Liverpool Telescope robotically
reacted and began observing the Swift GRB 090422 (Ukwatta et al.,
GCN Circ. 9185) using the r',i', and z' filters, corresponding to
2.40 min after the BAT trigger time.

Inside the revised XRT error circle we detect a single object of
r' ~ 19 mag, which is already present in the DSS archive images and
shows no significant fading from 10 min to 1 hr post burst.


GRB_name: GRB080408A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9188
SUBJECT: GRB 080408A: GAO 150cm telescope Optical Observation
DATE:    09/04/22 10:47:58 GMT
FROM:    Kenzo Kinugasa at Gunma Astro. Obs/Japan  <kinugasa@astron.pref.gunma.jp>

K. Kinugasa, H. Takahashi, S. Honda, O. Hashimoto, H. Taguchi
 (Gunma Astronomical Observatory) report:

 The field of GRB 090408 (Stroh et al. GCN 9110) was observed
with the 150 cm telescope of the Gunma Astronomical Observatory.
Starting at 16:03 UT and 18.36 UT (1.03 and 2.58 hours after the
trigger), Rc and Ic frames were acquired for sets of 5 x 3-min
and 5 x 3-min exposures under a hazy sky condition.

  We did not detect any new point source within the BAT error circle
to limiting magnitudes below relative to USNO-B1.0 R2 and I magnitudes.

mid-UT     exp       band       mag.
-----------------------------------
16:12:59   5x3min    Rc         > 20.1
16:34:40   5x3min    Ic         > 19.4

27:45:46   5x3min    Rc         > 20.3
28:15:37   5x3min    Ic         > 19.3


GRB_name: GRB090410A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9189
SUBJECT: GRB 080410: GAO 150cm telescope Optical Observation
DATE:    09/04/22 10:59:01 GMT
FROM:    Kenzo Kinugasa at Gunma Astro. Obs/Japan  <kinugasa@astron.pref.gunma.jp>

K. Kinugasa, S. Honda, O. Hashimoto, H. Takahashi, H. Taguchi
 (Gunma Astronomical Observatory) report:

 The field of GRB 090410 (Grupe et al. GCN 9122) was observed
with the 150 cm telescope of the Gunma Astronomical Observatory.
Starting at 18:33 UT (1.60 hours after the trigger), Rc and Ic frames
were acquired for 3 x 3-min and 5 x 3-min exposures under a high airmass
(sec z ~3) condition.

  We did not detect any new point source within the ground-calculated
BAT error circle (Barthelmy et al. GCN 9123) to limiting magnitudes
of Rc=19.0 and Ic=19.0 relative to USNO-B1.0 R2 and I magnitudes at the
meantime of 18:41 UT and 18:56 UT, respectively.


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9190
SUBJECT: GRB 090418A: RTT150 optical observations
DATE:    09/04/22 11:07:11 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>

I. Bikmaev, R.Zhuchkov, N. Sakhibullin (KSU/AST),
I. Khamitov, Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI) 

report:

The optical afterglow of GRB 090418A (Chornock et al., GCN 9148, Mangano et
al., GCN 9149) was observed with Russian-Turkish 1.5-m telescope (RTT150,
Bakirlitepe, TUBITAK National Observatory, Turkey) under moderate
transparences. We obtained series of 600s exposures in BVRc filters,
centered at April 18, 23:40 UT, i.e. 0.52 days after the burst.

The afterglow is clearly seen at combined R image, and marginally detected
at combined B,V frames.

Using the same calibration star USNO-B1.0 1234-0288651 as Pavlenko et
al. (GCN 9179), we estimate the following magnitudes of OT:

Filter, Exposure, mag.,     err.
         (s)
B       3x600     23.5    limit
V       3x600     22.7    limit
R       4x600     22.1    +/- 0.1

We made also series of 3x900 sec exposures in Rc filter centered on April
20, 23:00, i.e. 2.5 days after the burst. The afterglow was not detected on
the combined frame with a limit R=23.3 mag

RTT150 finding chart (Rc) can be found at:

http://hea.iki.rssi.ru/grb/090418a/indexeng.html


GRB_name: GRB090418B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9191
SUBJECT: GRB 090418B: RTT150 optical observations
DATE:    09/04/22 13:44:41 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>

I. Bikmaev, R.Zhuchkov, N. Sakhibullin (KSU/AST),
I. Khamitov, Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI) 

report:

The field of GRB 090418B (Copete et al., GCN 9159) was observed with
Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National
Observatory, Turkey). We obtained series of 3x300s exposures in Rc filter,
centered on April 19, 01:04 UT, i.e. 16 hours after the burst.  In addition,
a second epoch of 4x300 sec exposures was obtained in Rc filter on April 20,
0:17 UT.

Similarly to Guidorzi et al. (GCN 9176), Afonso et al. (GCN 9178), Nissinen
et al. (GCN 9181) we do not detect any obvious fading optical source inside
the BAT error circle. The upper limit for the first epoch of our
observations is Rc > 22.7 mag.


GRB_name: GRB090422A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9194
SUBJECT: GRB 090422: Enhanced Swift-XRT position
DATE:    09/04/22 16:44:16 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 6291 s of XRT Photon Counting mode data and 8 UVOT
images for GRB 090422, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 294.74967, +40.38445 which is equivalent
to:

RA (J2000): 19h 38m 59.92s
Dec (J2000): +40d 23' 04.0"

with an uncertainty of 1.5 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090422A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9195
SUBJECT: GRB 090422: Swift-BAT refined analysis
DATE:    09/04/22 17:39:45 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

C. B. Markwardt (GSFC/UMD), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090422 (trigger #349931)
(Ukwatta, et al., GCN Circ. 9185).  The BAT ground-calculated position is
RA, Dec = 294.746, 40.398 deg which is 
   RA(J2000)  =  19h 38m 59.1s 
   Dec(J2000) = +40d 23' 52.1" 
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 72%.
 
The mask-weighted light curve shows two main peaks at T0 and T+8 sec.
They are each about 1 sec wide. There is a third, weaker peat at ~T=50 sec.
T90 (15-350 keV) is 8.5 +- 0.4 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.4 to T+8.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.72 +- 0.30.  The fluence in the 15-150 keV band is 2.3 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.37 sec in the 15-150 keV band
is 1.7 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/349931/BA/


GRB_name: GRB090418A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9196
SUBJECT: GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
DATE:    09/04/22 20:08:42 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

V. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team,

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC),
W. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD),
D. Palmer (LANL), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), and T. Ukwatta (GWU)
on behalf of the Swift-BAT team,
report:

We performed the Konus-Wind and the Swift/BAT joint spectral analysis
of GRB 090418A (Swift/BAT trigger #349510: Mangano et al., GCN Circ. 
9149, Fenimore et al. GCN Circ. 9157).
Since the Konus-Wind observed this GRB in the waiting mode, we only
have 3 channel spectral data for the Konus-Wind which cover the energy
range from 20 keV to 1.2 MeV.  Therefore, the joint spectral analysis of
the Konus-Wind and the Swift/BAT data enables to derive the broad-band
spectral parameters of this burst.

The time interval of the spectral data for each instrument is chosen
from  T0(BAT)-6.7 to T0(BAT)+58.1 sec where T0(BAT) is the trigger time
of BAT at 11:07:40.2 UTC.  The energy ranges which we used in the joint
spectral analysis are 20-1200 keV and 14-150 keV for the Konus-Wind and
the Swift/BAT respectively.  The spectral data of two instruments are
fitted with the spectral model multiplied by the constant factor to take
into account the systematic effective area uncertainties in the response
matrices of each instrument.

The spectrum is well fitted with a power-law with exponential cutoff 
model: dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak). The constant factors 
of each instrument agree within 20%.  No systematic residual from the 
best fit model is seen in the spectral data of each instrument.  The 
best fit spectral parameters are: alpha = -1.30 +/- 0.09 and Epeak = 
610(-164, +530) keV (chi2/dof = 37.0/57).  The best fit spectral 
parameters for the GRB (Band) model fixing beta = -2.5 are: alpha = -1.30 
+/- 0.09, and Epeak = 601(-215, +554) keV (chi2/dof = 37.1/57).  The 
energy fluence in the 15-1200 keV band calculated by a power-law with 
exponential cutoff model for this 64.8 sec interval is (1.79 +/- 
0.21)x10^-5 erg/cm2.

All the quoted errors are at the 90% confidence level.

Assuming z = 1.6 (Chornock et al., GCN Circ. 9151) and a standard 
cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 
0.73, the isotropic energy  release is E_iso ~2x10^53 erg in 1 keV to 10 
MeV at the GRB rest frame extrapolating the best Band function fit 
fixing beta = -2.5.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090418A/


GRB_name: GRB090422A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9197
SUBJECT: GRB 090422: Liverpool Telescope possible candidate
DATE:    09/04/23 00:12:49 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), D. Bersier, C.G. Mundell (Liverpool JMU)
on behalf of a large collaboration report:

Following the distribution of the enhanced Swift-XRT position
(Beardmore et al. GCN Circ. 9194) of GRB 090422 (Ukwatta et al.
GCN Circ. 9185), we re-analysed the data acquired with the
Liverpool Telescope, mentioned in our previous report
(Guidorzi et al. GCN Circ. 9187).

Inside the enhanced XRT error circle we detect a single object
with magnitude of (21.7 +/- 0.3) in the r' filter, from 11 to 43
min post burst, at the following position (J2000):

RA=   19:38:59.91
Decl= +40:23:03.5

with an uncertainty of 0.7 arcsec. The calibration was done with
respect to nearby USNOB-1 stars, using the R2 magnitudes values.
This source is also detected in i' and z' filters.
At the moment we cannot assess whether the object is fading.
The source of r'~19 mag mentioned in our earlier report lies
outside the enhanced XRT error circle.
Further observations are planned.


GRB_name: GRB090423A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9198
SUBJECT: GRB 090423: Swift detection of a burst
DATE:    09/04/23 08:14:38 GMT
FROM:    Hans Krimm at NASA-GSFC  <krimm@milkyway.gsfc.nasa.gov>

H. A. Krimm (CRESST/GSFC/USRA), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), O. Godet (U Leicester), C. Gronwall (PSU),
C. Guidorzi (U Ferrara), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL), M. Perri (ASDC),
B. Sbarufatti (INAF-IASFPA), P. Schady (MSSL-UCL), G. Stratta (ASDC),
G. Tagliaferri (INAF-OAB) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 07:55:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090423 (trigger=350184).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 148.895, +18.160 which is 
   RA(J2000) = 09h 55m 35s
   Dec(J2000) = +18d 09' 37"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a double-peaked
structure with a duration of about 20 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 07:56:31.8 UT, 72.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 148.8879,
18.1497 which is equivalent to:
   RA(J2000)  = 09h 55m 33.08s
   Dec(J2000) = +18d 08' 58.9"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 44 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
2.89e+20 cm^-2 (Kalberla et al. 2005). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 77 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
BAT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.03. 




Burst Advocate for this burst is H. A. Krimm (krimm AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9199
SUBJECT: GRB 090418A: R and I band observation
DATE:    09/04/23 08:36:23 GMT
FROM:    Rupak Roy at ARIES  <rupakroy1980@gmail.com>

Brajesh Kumar, Rupak Roy, Brijesh Kumar and S. B. Pandey (ARIES,
NainiTal, India, on behalf of larger Indian GRB collaboration).

We have imaged the field of swift GRB 090418A (GCN 9149) with the 104
cm Sampurnanand Optical telescope at ARIES Nainital on 18th April 2009
at 19.815 hrs UT.
We do not detect any afterglow candidate in our co-added R_c and I_c
band images (exp time 1400sec in each band) within the error circle of
XRT (GCN 9163).
The Photometry of the co-added frames put a 3 sigma upper limit of R ~
20.64 and I ~ 19.65 mag in comparison to the nearby USNO - B1 stars.


GRB_name: GRB090423A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9200
SUBJECT: GRB 090423: Faulkes Telescope South observations
DATE:    09/04/23 09:42:02 GMT
FROM:    Andrea Melandri at Liverpool John Moores U  <axm@astro.livjm.ac.uk>

A. Melandri (Liverpool JMU), C. Guidorzi (U. Ferrara), C.G. Mundell,
D. Bersier (Liverpool JMU), P. O'Brien, N. Tanvir (U. Leicester) on
behalf of a large collaboration report:


On 2009 April 23 at 07:57:07 UT we observed the Swift-BAT GRB 090423
(Krimm et al., GCN Circ. 9198) with the 2-m Faulkes Telescope South.

Observations started 108 seconds after the BAT trigger time and were
performed using the B, R and i' filters. We could not find any
uncatalogued object inside the XRT error circle down to the following
limiting magnitudes:

For single frames:

Mid Time   Exposure  Filter   Limit
  (min)       (s)              (mag)
-------------------------------------
16.05         60      i'      > 18.0
21.30        120      r'      > 20.0
24.29        120      i'      > 19.0
-------------------------------------

For coadded frames:

Time Range   Exposure  Filter  Limit
  (min)         (s)             (mag)
-------------------------------------
13.58-53.82    660      r'     > 20.8
15.55-45.95    420      i'     > 20.5
-------------------------------------

Calibration was performed using few SDSS nearby stars on both filters.


GRB_name: GRB090423A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9201
SUBJECT: GRB 090423: P60 Observations
DATE:    09/04/23 09:46:20 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:

We have imaged the field of GRB090423 (GCN 9198, Krimm et al.) with the
automated Palomar 60-inch telescope beginning at 2009 23 April 7:58 UT (~
3 minutes after the burst) in the Sloan r', i', and z' filters.  In
coadded images we find no sources inside the XRT error circle to the
following limiting magnitudes (calculated with respect to several SDSS
stars in the field):

Mean UT  t_b (min) Filter  Magnitude
---------------------------------------------------------------------
23 Apr 08:11 16  r'  > 21.5
23 Apr 08:15 20  i'  > 21.5
23 Apr 08:17 22  z'  > 20.5

The lack of an optical afterglow, together with the fact that the X-ray
column density is consistent with the Galactic value (Krimm et al., GCN
9198), make GRB090423 an interesting candidate high-redshift event.  We
encourage observations at longer wavelengths to search for a NIR
counterpart.


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9202
SUBJECT: GRB 090423: UKIRT K-band observations
DATE:    09/04/23 10:51:23 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

N. Tanvir (U. Leicester), A. Levan (U. Warwick), T. Kerr (JACH),
T. Wold (JACH)

We observed the field of GRB 090423 with WFCAM on UKIRT, beginning at
08:16 (UT), approximately 20 minutes post-burst.  We detect a faint
source in the K-band image just outside the revised XRT error circle,
at coordinate:

 09 55 33.29  +18 08 57.8 (J2000, estimated uncertainty 0.3 arcsec)

The source has a magnitude K~17.5, but does not appear in SDSS images,
and therefore is very red. The image is also extended in the E-W
direction, and so might be (or include) a dusty host galaxy.  However,
we caution that the images are slightly trailed and so further work is
required to determine whether this source is a point source or not.


GRB_name: GRB090422A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9203
SUBJECT: GRB 090422: Swift/UVOT Upper Limits
DATE:    09/04/23 11:37:54 GMT
FROM:    Alice Breeveld at MSSL-UCL  <aab@mssl.ucl.ac.uk>

A. A. Breeveld (MSSL/UCL) and T. N. Ukwatta (GSFC/GWU) report on  
behalf of the Swift UVOT team:

     The Swift/UVOT observed the field of GRB 090422 starting 55 s  
after the BAT trigger (Ukwatta, et al., 2009, GCN Circ. 9185). Settled  
exposures started at T+74 s with a Finding Chart (FC) in the white  
filter. We do not find any new source, at the enhanced position of the  
XRT afterglow (Beardmore, et al. 2009, GCN Circ. 9194) nor at the  
position of the candidate found by the Liverpool Telescope (Guidorzi,  
et al. 2009, GCN Circ. 9197).  3-sigma upper limits for detecting a  
source in the white and u FCs, and subsequent co-added images in all  
filters are:

Filter           T_start   T_stop   Exp(s)      Mag
----------------------------------------------------------
white (FC)  74           224       147         >20.5
u (FC)          287        537        246        >19.6  

v                  617         11744   1317      >20.3
b                  542         18318   1145     >20.8
u                  690         24099   2059     >20.8
uvw1          666          23300   2203     >21.0
uvm2          641          22393   2092     >20.8
uvw2          592          10831   1318     >20.8
white          566          5591     341.4    >20.8
---------------------------------------------------------

The quoted upper limits have not been corrected for the expected  
Galactic extinction along the line of sight corresponding to a  
reddening of E_{B-V} = 0.198 mag (Schlegel, et al., 1998, ApJS, 500,  
525).  All photometry is on the UVOT photometry system described in  
Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090423A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9204
SUBJECT: GRB 090423: Swift-BAT refined analysis
DATE:    09/04/23 12:45:50 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090423 (trigger #350184)
(Krimm, et al., GCN Circ. 9198).  The BAT ground-calculated position is
RA, Dec = 148.891, 18.165 deg, which is 
   RA(J2000)  =  09h 55m 33.8s 
   Dec(J2000) = +18d 09' 55.7" 
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.
 
The mask-weighted light curve shows a couple overlapping peaks starting
at ~T-2 sec, peaking at T+4 sec, and ending at ~T+15 sec.
T90 (15-350 keV) is 10.3 +- 1.1 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.7 to T+11.7 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.80 +- 0.50, 
and Epeak of 48.6 +- 6.2 keV (chi squared 41.4 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 5.9 +- 0.4 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T+3.50 sec in the 15-150 keV band is
1.7 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.90 +- 0.10 (chi squared 59.9 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/350184/BA/


GRB_name: GRB090423A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9205
SUBJECT: GRB 090423: Enhanced Swift-XRT position
DATE:    09/04/23 12:52:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 3221 s of XRT Photon Counting mode data and 7 UVOT
images for GRB 090423, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 148.88830, +18.14937 which is equivalent
to:

RA (J2000): 09h 55m 33.19s
Dec (J2000): +18d 08' 57.7"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9206
SUBJECT: GRB 090423: UKIRT data further analysis
DATE:    09/04/23 13:05:45 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

A. Levan (U. Warwick), N. Tanvir (U. Leicester),
K. Wiersema (U. Leicester)

Further analysis of the data reported in GCN 9202 reveals that the
source did not fade appreciably (i.e. by more than ~0.15 mag) between
observations with mid-times 25 and 41 minutes post-burst.  However, we
do believe that the extension of the image is consistent with it
being a point source.

We note that the revised XRT error circle (GCN 9205) now contains this
source, making it likely the counterpart or host of this GRB.


GRB_name: GRB090423A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9207
SUBJECT: GRB090423, RIMOTS optical upper limits
DATE:    09/04/23 14:00:54 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

K.Kono, K.Noda, E.Sonoda, N.Ohmori, H.hayasi,
A.Daikyuji, Y.Nisioka, M.Yamauchi
(University of Miyazaki)

We have observed the field covering the error circle of
GRB090423 (Swift trigger 350184, GCN 9198, H. A. Krimm et al.)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 10:49:54 UT, about 3.0 hr
after the Swift trigger time.

We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog,
There is no new source at the reported position.
(GCN 9198, H. A. Krimm et al. GCN 9202, N. Tanvir et al.
GCN 9204, D. M. Palmer et al. GCN 9205, P. A. Evans et al. )

the upper limits are as follows:
--------------------------------------------------------------
Start(UT) End(UT) Num. of frames Limit (mag.)
--------------------------------------------------------------
10:49:54 10:50:24 1 16.5
10:49:54 11:45:01 45 19.4
---------------------------------------------------------------


GRB_name: GRB090422A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9208
SUBJECT: GRB 090422: Swift-XRT refined analysis
DATE:    09/04/23 14:58:43 GMT
FROM:    Matteo Perri at ISAC/ASDC  <perri@asdc.asi.it>

M. Perri and G. Stratta (ASDC) report on behalf of the Swift-XRT Team:

We have analysed the first 31 ks of Swift-XRT data obtained from
GRB 090422 (trigger 349931; Ukwatta et al., GCN Circ. 9185), starting
from T+70 s and ending at T+70 ks.

The best position of the X-ray afterglow is the UVOT-enhanced XRT
position given in Beardmore et al. (GCN Circ. 9194).

The 0.3-10 keV X-ray light curve is well described by a double broken
power-law model with decay indices alpha1=-1.7+/-0.2, alpha2=-0.2+/-0.3,
alpha3=-1.0+/-0.1 and temporal breaks t1=421+/-92 s and t2=1.5+/-0.3 ks .

The X-ray spectrum is well fit by an absorbed power-law model with a
photon index of 2.5+/-0.2 and a column density of (2.3+/-0.7)e21 cm**-2
in excess to the Galactic one in the direction of the source
(1.7e21 cm**-2, Kalberla et al. 2005). The count-rate to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.6(8.7)E-11 erg cm**-2 count**-1.

Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10 keV XRT count rate of 2e-3 count/s at T+48hr, which
corresponds to an observed 0.3-10 keV flux of ~7e-14 erg/cm**2/s.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00349931.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090423A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9209
SUBJECT: GRB 090423:  NIR photometry and evidence for spectral break
DATE:    09/04/23 15:02:30 GMT
FROM:    Derek Fox at PSU  <dfox@astro.psu.edu>

A. Cucchiara (PSU), D. B. Fox (PSU), and E. Berger (Harvard) report:

"On April 23.33 UT we imaged the field of Swift GRB 090423 (Krimm et
al., GCN 9198) with NIRI on the Gemini-North telescope.  We obtained
9x60 sec exposures in Y,J,H.  In the coadded J and H images we clearly
identify the object noted by Tanvir et al. (GCN 9202) and it appears
point-like (see also Levan et al., GCN 9206). The object is not
detected in Y-band.

We derive the following magnitudes, calibrated using three 2MASS stars
in the field:

J mag: 19.29 +- 0.07
H mag: 17.71 +- 0.14

The resulting J-H color of 1.1 AB mag is very red, corresponding to a
steep spectral slope of beta=3.8.  Taken in conjunction with a flat
H-K color (see GCN 9202), our non-detection in Y-band, and a red I-J
color of 1.7 AB mag in comparison to P60 limits (GCN 9201), we suggest
that there is a likely break in the spectrum at about 1.2 microns,
with extinction an unlikely explanation due to the sharpness of the
feature and the shallow slope to redder wavelengths.  If this is due
to Ly-alpha absorption, then the resulting redshift for GRB 090423 is
z~9.

Further analysis is in progress and additional observations are
planned."


GRB_name: GRB090423A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9210
SUBJECT: GRB090423 - Swift/UVOT upper limits.
DATE:    09/04/23 17:06:23 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <mdp@mssl.ucl.ac.uk>

  M. De Pasquale (MSSL/UCL) and H. Krimm (GSFC/GWU) report on
behalf of the Swift UVOT team:

The Swift/UVOT took the first settled exposure of GRB 090423 starting 
77 s after the BAT trigger (Krimm, et al., 2009, GCN Circ. 9198) in the 
white filter. We do not find any new source, at the enhanced position of 
the XRT afterglow (Evans, et al. 2009, GCN Circ. 9205) nor at the
position of the K band candidate found by UKIRT (Tanvir,
et al. 2009, GCN Circ. 9206). No source is detected even when all
the images of all filters are summed. The 3-sigma upper limits for
detecting a source in the white and u band first exposures, and
subsequent co-added images in all filters are:

Filter           T_start   T_stop   Exp(s)      Mag
----------------------------------------------------------
white               77      227     147         >20.7
u                   290     540     246         >20.0

v                  619      6162    413         >19.6
b                  545      5497    413         >20.2
u                  290      5342    462         >20.4
uvw1               668      6503    344         >20.1
uvm2               644      6367    413         >20.1
uvw2               594      5958    412         >20.5
white               77      5752    560         >21.3
---------------------------------------------------------

The quoted upper limits have not been corrected for the expected
modest Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.03 mag (Schlegel, et al., 1998, ApJS, 500,
525).  All photometry is on the UVOT photometry system described in
Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9211
SUBJECT: GRB090418A Rc-band photometry
DATE:    09/04/23 19:03:44 GMT
FROM:    Arne A. Henden at AAVSO  <arne@aavso.org>

A. Henden (AAVSO), J. Gross (SRO), B. Denny (DC-3),
D. Terrell (SwRI), and W. Cooney (SRO) report:

We obtained photometry of the GRB090418A afterglow
reported by Chornock et al. (GCN 9148) using the Sonoita
Research Observatory (SRO) 35cm telescope in southern
Arizona, utilizing an automatic VOevent trigger.  The
Rc-band exposures began about 2 minutes after the burst
and continued until twilight.  Ten 60-second and five
180-second exposures were acquired.

Astrometry of the afterglow from several images and
using UCAC as the reference catalog yields coordinates:
17:57:15.151 +33:24:20.93 J2000 (+/- 50mas)

Photometry, assuming that the star at
17:57:42.53 +33:25:47.2
has an R magnitude of 13.12

UT(mid)  delT  exp  Rc      err
11.1728   162  60  15.802  0.044
11.1919   231  60  16.185  0.048
11.2111   300  60  16.500  0.043
11.2303   369  60  16.818  0.058
11.2494   438  60  17.019  0.066
11.2686   507  60  17.249  0.067
11.2878   576  60  17.440  0.063
11.3069   645  60  17.605  0.105
11.3261   714  60  17.680  0.089
11.3450   782  60  17.855  0.115
11.3958   965 180  18.007  0.104
11.6522  1888 180  18.778  0.129
11.7067  2084 180  18.919  0.138
11.7592  2273 180  18.960  0.142
11.8114  2461 180  18.891  0.196

Where delT is the time in seconds from the burst (Mangano et al.,
GCN 9149), and the exposure is in seconds. The optical afterglow
candidate is in the filter reflection halo from HD163948,
a 6.9mag star about 2arcmin distant, so the last
few magnitudes may have a systematic bias.

We note that this field was not calibrated by SDSS through DR6.
We will perform a BVRI calibration over the next few nights.


GRB_name: GRB090423A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9212
SUBJECT: GRB 090423: Swift-XRT refined analysis
DATE:    09/04/23 20:06:55 GMT
FROM:    Matteo Perri at ISAC/ASDC  <perri@asdc.asi.it>

G. Stratta and M. Perri (ASDC) report on behalf of the Swift-XRT Team:

We have analysed the first 8.4 ks of Swift-XRT data obtained from
GRB 090423 (trigger 350184; Krimm et al., GCN Circ. 9198), starting
from T+110 s and ending at T+18 ks.

The best position of the X-ray afterglow is the UVOT-enhanced XRT
position given in Evans et al. (GCN Circ. 9205).

The 0.3-10 keV X-ray light curve during the first Swift orbit shows a
flare peaking at T+170s. Starting from the second orbit (T+3.9 ks) the
curve is well described by a power-law model with index alpha=-1.3+/-0.1.

The X-ray spectrum during the power-law decay is well fit by an
absorbed power-law model with a photon index of 2.0+/-0.1 and a
total column density of (8.7+/-2.5)e20 cm**-2. The Galactic column
density in the direction of the source is 2.9e20 cm**-2
(Kalberla et al. 2005). The count-rate to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum is
3.7(4.6)E-11 erg cm**-2 count**-1. Errors are given at the
1-sigma level.

We note that the X-ray column density is consistent, within 3 sigma,
with the Galactic value, consistent with the possibility that the burst
is at high redshift, as reported by Cucchiara et al. (GCN Circ. 9209).

Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10 keV XRT count rate of 5e-3 count/s at T+24 hr, which
corresponds to an observed 0.3-10 keV flux of ~2e-13 erg/cm**2/s.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00350184.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090423A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9213
SUBJECT: GRB 090423:  Correction to NIR photometry 
DATE:    09/04/23 20:36:32 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara, D. B. Fox (PSU), and E. Berger (Harvard) report:

"Further analysis of our Gemini+NIRI H-band imaging (Cucchiara, Fox &
Berger, GCN 9209) has led to a significant correction in the H-band
magnitudes for the afterglow/host (Tanvir et al., GCN 9202) of GRB
090423 (Kimm et al., GCN 9198).  Our revised magnitudes for this
object are:

J mag: 19.29 +- 0.07
H mag: 18.57 +- 0.07

The revision to the H-band magnitude, in addition to the absence of
any detection in our Y-band images, suggests a break in the spectrum
below or within the J-band and above the Y-band, yielding, e.g., 7<~z<~9
in a Lyman-alpha interpretation.

Further analysis is in progress and additional observations are planned.

We apologize for any inconvenience."


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9214
SUBJECT: GRB 090423: NOT z-band limit
DATE:    09/04/23 23:17:44 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

D. Malesani (DARK/NBI), H. Dahle, I. Skorbakk (ITA, Oslo), E. Wuyts 
(Univ. Chicago), P. Jakobsson (Univ. Iceland), J. P. U. Fynbo, J. Hjorth 
(DARK/NBI), report on behalf of a larger collaboration:

We observed the field of GRB 090423 (Krimm et al., GCN 9198) with the 
Nordic Optical Telescope equipped with the MOSCA camera. Observations 
were carried out using the SDSS z' filter, starting on Apr 23.874 UT 
(13.0 hr after the GRB trigger) and with a total exposure time of 1 hr.

At the position of the NIR candidate afterglow (Tanvir et al., GCN 9202; 
Levan et al., GCN 9206; Cucchiara et al., GCN 9209), we do not detect 
any source down to a limiting magnitude z(AB) > 23.7, calibrated using 
the SDSS catalog.

We acknowledge excellent support from the NOT visiting observers.


GRB_name: GRB090423A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9215
SUBJECT: GRB 090423: GROND detection and preliminary photo-z
DATE:    09/04/24 03:05:49 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

F. Olivares, T. Kruehler, J. Greiner, R. Filgas (all MPE Garching) report on 
behalf of the GROND team:

We observed the field of GRB 090423 (Swift trigger 350184, H. Krimm et 
al., GCN #9198) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m 
MPI/ESO telescope at La Silla Observatory (Chile). Observations started on 
23 Apr. 2009 at 23:08 UT, 15.2 h after the burst.

We detect the source within the XRT error circle (Evans et al. 2009, GCN #9205)
reported by Tanvir et al. (GCN #9202), Levan et al. (GCN #9206) and Cucchiara 
et al. (GCN# 9209) in the NIR channels.

Preliminary photometry yields the following magnitudes and upper limits in 
stacked images at a midtime of 16.7 h after the burst, obtained using 
SDSS/2MASS stars as reference:

Filter  Exp [s]    AB Mag   MagErr
----------------------------------
g'      16 x 369    > 25.0
r'      16 x 369    > 25.1
i'      16 x 369    > 24.2
z'      16 x 369    > 24.0
J       480 x 10    21.6     0.1
H       480 x 10    21.2     0.1
K       480 x 10    20.9     0.1

These magnitudes imply a significant fading to what was reported earlier 
(GCNs #9202, #9213) and confirm this source to be the afterglow of GRB 
090423. Furthermore, we confirm the red z-J color, and thus the probable 
high redshift nature of this event. After correcting for the foreground
galactic extinction of E(B-V)=0.029 (Schlegel et al. 1998) and assuming no
intrinisic extinction, a fit with Hyper-z (Bolzonella et al. 2000) results 
in a spectral index of 1.0 (+0.4,-0.5), comparable to that observed in 
X-rays (Stratta & Perri, GCN #9212), and a preliminary photometric redshift 
of z = 8.0+0.5-1.2.


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9216
SUBJECT: GRB 090423: TNG Amici spectrum
DATE:    09/04/24 03:17:30 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

C. C. Thoene (INAF-OAB), P. D'Avanzo (INAF-OAB/U. Bicocca), A.
Fernandez-Soto (IFCA-Santander), S. Campana, D. Fugazza (INAF-OAB), 
L.A. Antonelli (INAF-OAR), G. Chincarini (Univ. Bicocca), S. Covino
(INAF-OAB), V. D'Elia (INAF-OAR), A. De Ugarte-Postigo (ESO), D.
Malesani (Dark/NBI), E. Palazzi (IASF-Bo), R. Salvaterra (INAF-OAB), A.
Fiorenzano (TNG) report, on behalf of a larger collaboration:

We observed the afterglow of GRB 090423 (Krimm et al. GCN 9198; Tanvir 
et al. GCN 9202; Levan et al., GCN 9206; Cucchiara et al., GCN 9209) 
with the Italian TNG 3.6m telescope located in the Canary Islands 
(Spain). The observations were performed using the Amici grism. We took 
a 2 hrs spectrum starting around Apr 23 at 22:16 UT (about 14.35 hours 
after the burst) and covering the range 600-2700 nm with a resolution of 
R ~ 50.

A preliminary analysis of the combined spectrum shows a very weak signal 
at the position of the NIR afterglow. No signal is observed below 
observed lambda ~ 10500 Angstrom. Assuming that the lack of signal at 
bluer wavelengths is due to Ly-alpha absorption in the IGM this gives a 
redshift of z ~ 7.6 (in agreement with the estimate of Olivares et al., 
GCN 9215). We point out that our wavelength calibration is based on an 
archival wavelength table.

We are very grateful for the excellent support of the TNG staff.

[GCN OPS NOTE(24apr09): Per author's request, the author list was revised.]


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9217
SUBJECT: GRB 090423: Deep z-band upper limit and confirmation of photo-z
DATE:    09/04/24 03:51:52 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, S. B. Cenko, and J. S. Bloom (UC Berkeley) report on
behalf of GRAASP:

We initiated a series of 15 x 200 second exposures of the field of GRB
090423 (Krimm et al, GCN 9198) in z-band using GMOS on Gemini-South
starting at 23:38 UT on 2009-04-23, 15.71 hours after the trigger.  No
source is visible in the XRT error circle (Evans et al., GCN 9205) or
the NIR position (Tanvir et al., GCN 9202) in the co-added image.  We
estimate a limiting magnitude (3-sigma) of:

z > 26.0 mag (t_mid = 16.25 hr)

This observation is nearly co-eval with the GROND photometry (Olivares
et al., GCN 9215) which detects the counterpart with a magnitude of J_AB
= 21.6, implying a color of J-z > 4.4 (AB).  This, along with the
non-detection of a lower-redshift host galaxy candidate, the TNG
spectrum (Thoene at al., GCN 9216), and the nearly flat JHK SED,
confirms the very high redshift (z > 7) of this event.

We thank Eleazar Carrasco and the Gemini observing staff for acquiring
these observations.


GRB_name: GRB090423A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9218
SUBJECT: GRB 090423: Near infrared observation at Okayama Observatory
DATE:    09/04/24 04:03:34 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

M. Yoshida, K. Yanagisawa, D. Kuroda, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 090423 (Krimm et al. GCN 9198) with a
near-infrared camera ISLE attached to the 188cm telescope of Okayama
Astrophysical Observatory. We also obtained optical data using the
optical three color CCD camera attached to the MITSuME 50cm
telescope.

We started the observation at 2009-04-23 10:32:27 UT, 2hr 37m after
the burst. We detected a very faint source close to the position of
the afterglow candidate reported by Tanvir et al. (GCN 9202) in our
J band image. The coordinate of the source is
    J2000   9h 55m 33.3s  +18d 08m 57.1s .
J band magnitude of the source is 20.1 mag, which is much fainter
than the previous report (Cucchiara et al. GCN 9213).

We could not find any new source in the optical bands and the other
near-infrared bands (H and Ks). The results of our photometry are
listed below. We used three 2MASS stars near the burst for near-
infrared flux calibration and GSC2.3 catalog for optical flux
calibration.


Near-infrared observation
Band    Mid-UT     Td(day)      EXP-T      mag
------------------------------------------------------
J       10:53:33   0.12377      720s    20.1 $B!^(B 0.3
H       11:04:30   0.13138      960s    > 19.3
Ks      10:56:31   0.12584      480s    > 18.7
------------------------------------------------------


Optical observation
 Mid-UT     Td(day)        EXP-T        g'     Rc     Ic
------------------------------------------------------------
11:43:56    0.15876        5940s     >20.4   >20.2  >19.5
------------------------------------------------------------


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9219
SUBJECT: GRB 090423: VLT/ISAAC spectroscopy
DATE:    09/04/24 07:20:35 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

N. Tanvir (U. Leicester), A. Levan (U. Warwick), K. Wiersema (U.
Leicester), J. Fynbo, J. Hjorth (DARK/NBI), P. Jakobsson (Reykjavik)
report on behalf of a larger collaboration:

We observed the afterglow of GRB 090423 with ISAAC on the VLT,
beginning about 01:30 (UT), approximately 17.5 hours post-burst.

Our provisional analysis shows a clear continuum at red wavelengths,
but no flux below about 11200A, consistent with a break due to
Lyman-alpha at a redshift z~8.2.  However, we caution that we have not
yet carefully calibrated the instrumental response, and further work
is required to confirm this result.

We thank the VLT observers for their excellent support in obtaining
these data, particularly Valentin Ivanov and Giovanni Carraro.


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9220
SUBJECT: GRB 090423 limiting magnitudes
DATE:    09/04/24 11:36:15 GMT
FROM:    Arne A. Henden at AAVSO  <arne@aavso.org>

A. Henden (AAVSO), J. Gross (SRO), B. Denny (DC-3),
D. Terrell (SwRI), and W. Cooney (SRO) report:

We observed the field of GRB 090423 (Krimm et al., GCN 9198)
using the 35cm telescope of Sonoita Research Observatory
with an automated VOevent trigger for an R-band image
sequence.  Images began at 07:58:09UT on 2009-04-23,
170 seconds after the burst, under good conditions.

The afterglow candidate reported by Tanvir et al. (GCN 9202),
Levan et al. (GCN 9206), Cucchiara et al. (GCN 9209),
and shown by Olivares et al. (GCN 9215) to have both faded
and to have a photo-z of 8.0, is not detected in our images.
We place 3-sigma constraints of

200 seconds midpoint (1min image)  Rc < 18
350 seconds midpoint (6min stack)  Rc < 20

using USNO-A red magnitudes.  The 19 total images, covering
the period 07:58:09 through 08:47:34, can be obtained from
ftp://ftp.aavso.org/public/sro/grb090423/


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9221
SUBJECT: GRB090423: Y-band field calibration
DATE:    09/04/24 12:43:12 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, Y. Jeon, C. Choi, W. Park, I. Lee Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

  We took a series of Y-band photometry calibration data
  for the field of GRB090423 using the 1.0m telescope at
  Mt. Lemmon (Arizona, US) operated by the Korea Astronomy
  Space Science Institute.

   For the Y-band photometry standards, we used P239-C and
  GD140 from UKIRT faint standards, and HIP 50459, a A0V star
  from Hipparcos catalog. The zero points obtained for
  these standards are applied to our observation of
  the GRB090423 field, yielding Y-band photometry (Vega) for
  objects in the GRB field down to Y(MKO) ~ 17.5 magnitude at 10-sigma.
  The expected zero point accuracy is ~0.1mag.
  To derive AB mag, add 0.63 mag to the values listed in
  the catalog.

  The calibration data and finding charts are available at
  http://astro.snu.ac.kr/~mim/grb/readme
  http://astro.snu.ac.kr/~mim/grb/grb090423_ycal.dat
  http://astro.snu.ac.kr/~mim/grb/yobj.reg
  http://astro.snu.ac.kr/~mim/grb/chart.gif

  We thank the LOAO operator, J. Yoon for his assistance for this
  observation.


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9222
SUBJECT: GRB 090423: Refined TNG analysis
DATE:    09/04/24 14:16:29 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

A. Fernandez-Soto (IFCA-Santander), F. Mannucci (INAF-OAA), D. Fugazza 
(INAF-OAB), L.A. Antonelli (INAF-OAR), S. Campana (INAF-OAB), G. 
Chincarini (Univ. Bicocca), S. Covino (INAF-OAB), P. D'Avanzo 
(INAF-OAB/U. Bicocca), V. D'Elia (INAF-OAR), M. Della Valle 
(INAF-OACa/ESO), A. Fiorenzano (TNG), C. Guidorzi (Univ. Ferrara), E. 
Maiorano (IASF-Bo), J. Mao (INAF-OAB), R.  Margutti (INAF-OAB/Univ. 
Bicocca), S. Marinoni (TNG), E. Palazzi (IASF-Bo), C. C. Thoene (INAF-OAB)
report, on behalf of a larger collaboration (CIBO):

We have performed an in-depth analysis of the TNG spectrum of GRB090423 
taken on Apr 23 at 22:16 UT with the NICS/Amici combination (Thoene et 
al, GCN 9216). We have corrected the wavelength calibration, now based 
both on the observation of sky features and a fit to the instrument 
sensitivity.

We detect in the spectrum flux at wavelengths lambda>1.1 microns, and a 
flux compatible with zero below that limit. Interpreting this wavelength 
as the onset of Lyman alpha absorption in the IGM, this leads us to 
deduce a value of z~8.1.

We have also analysed all the available photometry (GCNs 9200, 9201, 
9202, 9206, 9209, 9210, 9213, 9214, 9215, 9217, 9218 and 9220) and find 
that the data are well fit by an afterglow without intrinsic dust 
obscuration, a photometric redshift 7.6<z<8.5, and a temporal decay 
index 0.50.

[GCN OPS NOTE(24apr09): Per author's request, Marinoni was added
to the author list.]


GRB_name: GRB090424A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9223
SUBJECT: GRB 090424: Swift detection of a burst with an optical counterpart
DATE:    09/04/24 14:23:57 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
P.A. Curran (MSSL-UCL), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), C. Gronwall (PSU), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), J. Mao (INAF-OAB),
R. Margutti (Univ Bicocca&OAB), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), K. L. Page (U Leicester),
P. Romano (INAF-IASFPA), B. A. Rowlinson (U Leicester),
M. H. Siegel (PSU), M. C. Stroh (PSU), G. Tagliaferri (INAF-OAB) and
L. Vetere (PSU) report on behalf of the Swift Team:

At 14:12:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090424 (trigger=350311).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 189.538, +16.829 which is 
   RA(J2000)  =  12h 38m 09s
   Dec(J2000) = +16d 49' 46"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several bright peaks
in the first 5 seconds, and then several smaller peaks at T+8, +15,
and +50 sec.  Total duration of about 60 sec.  The peak count rate
was ~50000 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 14:13:33.8 UT, 84.5 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 189.5213, +16.8364 which is equivalent to:
   RA(J2000)  = 12h 38m 05.11s
   Dec(J2000) = +16d 50' 11.0"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 63 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 91 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 12:38:05.11 = 189.52128
  DEC(J2000) = +16:50:15.1  = 16.83753
with a 90%-confidence error radius of about 0.74 arc sec. This position is 4.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.29 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.03. 

Burst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9224
SUBJECT: GRB 090424: ROTSE-III Confimation of Optical Counterpart
DATE:    09/04/24 14:35:53 GMT
FROM:    Fang Yuan at ROTSE  <yuanfang@umich.edu>

F. Yuan (U Mich), report on behalf of the ROTSE collaboration:

ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded  
to GRB 090424 (Swift trigger 350311;Cannizzo et al, GCN 9223). The  
first image started at 14:18:41.4 UT, ~6 min after the burst. The  
unfiltered images are calibrated relative to USNO A2.0. We detect a  
fading source at the position consistent with the UVOT OT, at the  
following magnitude:


start UT     mag     mlim(of image)
----------------------------------
14:18:41.4     15.5     17.2


This source is not visible in DSS (second epoch), 2MASS or the  
MPChecker database.

A jpeg image is available at http://www.rotse.net/images/gsb350311_3a001-010_key.jpg 
  Note that the object marked 12 is the candidate in question.

Continuing observations are in progress. 


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9225
SUBJECT: GRB 090424: TNT optical observations
DATE:    09/04/24 15:21:45 GMT
FROM:    W.K. Zheng at NAOC  <zwk@bao.ac.cn>

L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei,
j. Wang, J.S. Deng, Y. Urata and J.Y. Hu 
on behalf of EAFON report:

TNT quickly responsed to the GRB 090424 (Swift trigger 350311;
Cannizzo et al. GCN 9223) in automatical mode, the first
images was taken start 14:13:36, 87s after the burst.
The optical afterglow (Cannizzo et al. GCN 9223; Yuan GCN 9224)
was clearly detected in our early white and R bands images,
after preliminary reduction, we estimated the afterglow have
faded about 3.5 mag from ~100s to ~1000s after the burst. 
Observation is still under going.

This message may be cited.


GRB_name: GRB090424A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9226
SUBJECT: GRB 090424: SDSS Galaxy at the Swift position
DATE:    09/04/24 15:23:49 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans (U. Leicester) and S.T. Holland (CRESST/USRA/GSFC) report:

We note the presence of the extended source  SDSS J123805.09+165014.6 in 
the UVOT error circle of GRB 090424 (Cannizzo et al. GCN Circ 9223); 
0.1" away from the Swift-UVOT position. This potential host galaxy has a 
photo-z of 0.26. GRB 090424 was detected in the u-band by Swift/UVOT, 
which is consistent with a low redshift origin of the burst.


GRB_name: GRB090423A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9227
SUBJECT: GRB 090423: Ep,i - Eiso correlation
DATE:    09/04/24 15:40:24 GMT
FROM:    Lorenzo Amati at INAF-IASF/Bologna  <amati@iasfbo.inaf.it>

L. Amati (INAF/IASF Bologna, Italy), F. Frontera (Univ. Ferrara and INAF/IASF 
Bologna, Italy), C. Guidorzi (Univ. Ferrara, Italy), E. Palazzi (INAF/IASF 
Bologna, Italy) report:

On the basis of the spectral parameters and fluence measured by Swift/BAT 
(Palmer et al., GCN 9204) and the redshift of ~7.5 - 8.5 suggested by 
photometry and spectroscopy of the optical counterpart (Cucchiara et al., 
GCN 9213; Olivares et al., GCN 9215; Thoene et al., GCN 9216; Perley et 
al., GCN 9217; Tanvir et al., GCN 9219; Fernandez-Soto et al., GRB 9222) 
we find that GRB 090423 is fully consistent with the Ep,i - Eiso 
correlation (Ep,i ~ 440 keV and Eiso ~10^53 erg for z = 8, assuming 
a flat LambdaCDM cosmology with H0=70 km/s/Mpc and Omega_M = 0.27).

In addition, the track of this GRB in the Ep,i - Eiso plane 
(http://www.iasfbo.inaf.it/~amati/grb090423.ps) implies a lower limit to 
the redshift of 1.4 (68% c.l.) and 0.9 (90% c.l.) in order to be 
consistent with the correlation. This further suggests that the event is 
not a local very reddened GRB.

This message may be cited.


GRB_name: GRB090422A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9228
SUBJECT: GRB 090422: Fermi GBM observation
DATE:    09/04/24 15:57:39 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

Sheila McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:

"At 03:35:17.07 UT on 22 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090422 (trigger 262064119 / 090422150)
which was also detected by the Swift-BAT (Ukwatta et al. 2009, GCN 9185
& Markwardt et al. 2009, GCN 9195). The GBM on-ground location is
consistent with the Swift position.
The angle from the Fermi LAT boresight is 29 degrees.

The GBM light curve consists of 2 pulses
with a duration (T90) of about 10 s (8-1000 keV).
The time-averaged spectrum from T0-2.4 s to T0+10.8 s is
adequately fit by a simple power law function with
index 1.81 +/- 0.15 (chi squared 358 for 361 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.0 +/- 0.1)E-6 erg/cm^2. The 0.128 sec peak photon flux measured
starting from T0-0.256 s in the 8-1000 keV band
is 7.8 +/- 0.5 ph/s/cm^2.


GRB_name: GRB090423A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9229
SUBJECT: GRB 090423: Fermi GBM observation
DATE:    09/04/24 17:04:54 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 07:55:25.39 UT on 23 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090423 (trigger 262166127 / 090423330)
which was also detected by the Swift (H. A. Krimm et al. 2008, GCN 9198)
The GBM on-ground location is consistent with the Swift position.
 
The angle from the Fermi LAT boresight is 75.6 degrees.

The GBM light curve shows a single structured peak 
with a duration (T90) of about 12 s (8-1000 keV). There is an 
indication for extended emission until 30 s after the burst onset.
The time-averaged spectrum from T0-7.040 s to T0+5.248 s is 
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.77 +/- 0.35 and
the cutoff energy, parameterized as Epeak, is 82 +/- 15 keV
(chi squared 275 for 238 d.o.f.). At a redshift of about 8 
(F. Olivares et al. 2008, GCN 9215; C. Thoene et al. 2008, GCN 9216; 
N. Tanvir et al. 2008, GCN 9219), the Epeak in the GRB rest frame, 
Epeak_rest, is 738 +/- 135 keV.

The event fluence (8-1000 keV) in this time interval is 
(1.1 +/- 0.3)E-06 erg/cm^2. Using standard cosmology 
(Omega_matter = 0.27, Omega_lambda = 0.73, H0=71) the 
isotropic equivalent energy in the 8-1000 keV band is 
E_iso = (8.9 +/- 2.4)E+53 ergs. The 1-sec peak photon 
flux measured starting from T0-1.920 s in the 8-1000 keV 
band is 3.3 +/- 0.5 ph/s/cm^2.

The spectrum can also be fit by using a Band function with 
Epeak = 54 +/- 22 keV and beta = -2.1 +/- 0.3. However alpha 
is poorly constrained.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090424A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9230
SUBJECT: GRB 090424: Fermi GBM Observation
DATE:    09/04/24 17:46:24 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

Valerie Connaughton (UAH) reports on behalf of the Fermi GBM Team:

"At 14:08:12.67 UT on 24 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090424 (trigger 262275130 / 090424592).
which was also detected by the Swift-BAT
(J. Cannizzo et al. 2009, GCN 9223).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 71 degrees, increasing
after trigger time.

The GBM light curve shows an intense, multi-peaked
emission period lasting around 6 sec, tailing off
into smaller peaks until about 20 sec after trigger time,
followed by a smaller peak between 45-60 sec after the trigger.  
The duration (T90) between 8 and 1000 keV is about 52 sec.
 
The time-averaged spectrum of the peak from T0-0.3 s to T0+5.5 s is
best fit by a Band function with Epeak = 177 +/- 3 keV,
alpha = 0.90 +/- 0.02, and beta = -2.9 +/- 0.1

The event fluence (8-1000 keV) over the entire event (-0.3 s to 59 s) is
(5.2 +/- 0.1)E-05 erg/cm^2. The 0.128-sec peak photon flux measured
at 1.4 s in the 8-1000 keV band is 137 +/- 5 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090424A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9231
SUBJECT: GRB 090424: Swift-BAT refined analysis
DATE:    09/04/24 19:20:50 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), A. M. Parsons (GSFC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090424 (trigger #350311)
(Cannizzo, et al., GCN Circ. 9223).  The BAT ground-calculated position is
RA, Dec = 189.531, 16.829 deg which is 
   RA(J2000)  =  12h 38m 07.4s 
   Dec(J2000) = +16d 49' 45.9" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 12%.
 
The mask-weighted light curve shows several overlapping bright peaks
starting at about T-2sec and ending at about T+5 sec.  There are 3 much
weaker, and broader, peaks at T+7, +15, and +50 sec.  The emission returns
to background at around T+150 sec.  T90 (15-350 keV) is 48 +- 3 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-0.7 to T+103.2 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.19 +- 0.15, 
and Epeak of 108.6 +- 20.3 keV (chi squared 45.8 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.1 +- 0.0 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T-0.10 sec in the 15-150 keV band is
71.0 +- 2.0 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.62 +- 0.03 (chi squared 72.0 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/350311/BA/


GRB_name: GRB090424A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9232
SUBJECT: GRB 090424: Enhanced Swift-XRT position
DATE:    09/04/24 19:40:43 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 564 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 090424, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 189.52107, +16.83773 which is equivalent
to:

RA (J2000): 12h 38m 5.06s
Dec (J2000): +16d 50' 15.8"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9233
SUBJECT: GRB 090424: MASTER-Net prompt optical observations 
DATE:    09/04/24 21:01:23 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov
Sternberg Astronomical Institute, Moscow State University

K.Ivanov, S.Yazev
Irkutsk State University

A. Tlatov, A.V. Parhomenko,
Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinski, I.Zalognikh, T.Kopytova
Ural State University, Kourovka


There are 6 MASTER Very Wide Field cameras located at Kislovodsk and Irkutsk 
with common FOW = 6000 square degrees (http://observ.pereplet.ru/).

One of the two  MASTER Very Wide Field Cameras located at Irkutsk
(D=50 mm, 2x1000 square degrees, 11 Mpx, 72" per pix in binning regime) 
has observed  UVOT error box (Cannizzo et al., GCN 9223) with 1s exposure 
befoure, during and after GRB Time without time gap between images.
The error box is near at the center of our FOW.

Our unfiltered images are calibrated relative to Tycho stars (V).
The magnitude limit of the each emage is  ~8 m at the center of FOW (some 
cloudy on the sky). The limit of coadded five images ~ 9 m.

The reduction is continued.

The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090424A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9234
SUBJECT: Swift/UVOT observations of GRB 090424
DATE:    09/04/24 21:42:37 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

P.Schady (MSSL/UCL) and J. K. Cannizzo (NASA/UMBC) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT started settled observations of the burst GRB090424 
(Cannizzo et al. GCN Circ. 9223) with the finding chart (fc) exposure in 
white, 167s after the BAT trigger. The afterglow is detected in the all 
filters at the position reported by Cannizzo et al. (GCN Circ. 9223), 
placing an upper limit on the redshift of ~1.3.  The combined UVOT data 
indicates that the afterglow is fading with a decay index of alpha ~ 0.9.

The UVOT magnitudes our reported below:

Filter    Tmid(s)   Exp(s)   Magnitude
white (fc) 167        147.4   15.27 +/- 0.01
u (fc)     429        245.8   16.40 +/- 0.03

white      594        19.4    16.99 +/- 0.07
v          644        19.5    16.86 +/- 0.19
b          570        19.5    17.27 +/- 0.13
u          1122       19.5    17.44 +/- 0.20
uvw1       695        19.5    16.81 +/- 0.19
uvm2       670        19.4    17.39 +/- 0.34
uvw2       793        19.4    17.51 +/- 0.27

The values quoted above are in the UVOT photometric system (Poole et al. 
2008, MNRAS, 383, 627) and are not corrected for the expected Galactic 
extinction corresponding to a reddening of E(B-V)=0.025 mag in the 
direction of the burst (Schlegel et al. 1998).


GRB_name: GRB090423A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9235
SUBJECT: GRB 090423: energetic, luminosity and jet break
DATE:    09/04/24 21:57:44 GMT
FROM:    Giancarlo Ghirlanda at INAF/Brera  <giancarlo.ghirlanda@brera.inaf.it>

L. Nava (INAF-OAB/Univ.Insubria); D. Burlon (MPE-Garching);
G. Ghirlanda (INAF-OAB); G. Ghisellini (INAF-OAB); M. Nardini (SISSA)

With the spectral parameters and fluence of GRB090423 as measured by  
Fermi (von Kienlin et al., GCN 9229)
and given its redshift z=8.1 (Fernandez-Soto et al., GCN 9222), we  
estimate the isotropic equivalent energy
Eiso = 1.03E53 and the isotropic equivalent peak luminosity Liso =  
1.88E53 (the value of Eiso is consistent
with that obtained with the Swift spectral results given in Palmer et  
al. GCN 9204).

Given the rest frame peak energy Ep= 746 keV, we show ( http://www.brera.inaf.it/utenti/ghirla/GRB/090423.html 
  )
that GRB090423 is consistent both with the Ep-Liso correlation  
(Yonetoku et al. 2004) and with the Ep-Eiso
correlation (Amati et al. 2002, Ghirlanda et al. 2008, Nava et al.  
2008; see also GCN 9227).

Noteworthly, GRB090423 is remarkably similar to GRB 080913 and GRB  
071020 with respect to the Amati and
Yonetoku correlations. It is worth mentioning that these three GRBs  
are long bursts according to their observed
T90 (12 s, 8 s and 4 s respectively) although, given their  redshifts,  
T90 ~ 1 sec in the rest frame.

Finally, considering the collimation corrected Ep-Egamma correlation  
(e.g. Ghirlanda et al. 2007), we estimate that a
jet break should occur in the afterglow light curve between ~22 and 54  
days (1 sigma consistency) or between ~10 and  130 days
(3 sigma consistency) assuming a homogeneous circum-burst environment  
with standard parameters
(see Nava et al. 2006, Ghirlanda et al. 2007). However, this break may  
not be observed in the
X-ray which, given the typical steep-flat-steep decay already observed  
for this burst
( http://www.swift.ac.uk/xrt_curves/00350184/ ), could likely be due  
to another emission component (e.g. Ghisellini et al. 2009).

This message may be cited.


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9236
SUBJECT: GRB 090424: Optical observations from 1.23m CAHA
DATE:    09/04/24 22:59:07 GMT
FROM:    Javier Gorosabel at IAA-CSIC  <jgu@iaa.es>

J. Gorosabel, P. Kubanek , M.  Jelinek (IAA-CSIC), A. de Ugarte  
Postigo (ESO),
J. Aceituno (CAHA), report on behalf of a larger collaboration:

We have observed the field of GRB 090424 (Cannizzo et al., GCN 9223)  
with
the 1.23m telescope at Calar Alto. The afterglow is clearly detected  
in BVRI-bands.
On April 24.87 UT the afterglow showed a magnitude of R = 19.3 +/-  
0.1, as
compared to stars from the USNO-B1.0.

Calar Alto is operated jointly by MPIA and IAA-CSIC.

Further observations are ongoing.


GRB_name: GRB090424A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9237
SUBJECT: GRB 090424: Swift-XRT refined analysis
DATE:    09/04/24 23:15:47 GMT
FROM:    Raffaella Margutti at U. di Milano Bicocca  <raffaella.margutti@brera.inaf.it>

R. Margutti (Univ. Bicocca & INAF-OAB), C. Guidorzi (Univ. Ferrara),
J. Mao (INAF-OAB)  and J. K. Cannizzo (NASA/UMBC) report on behalf of
the Swift-XRT team:

We have analysed the first 2 orbits of Swift-XRT data obtained for
GRB 090424 (Cannizzo et al. GCN Circ. 9223), covering 1732 s of
Windowed Timing (WT) and 1329 s of Photon Counting (PC) mode data,
respectively, between 88 s and 8 ks after the trigger.
The UVOT-enhanced XRT position was given by Goad et al. in GCN Circ. 9232.

The light-curve can be modelled by a double broken power-law, with
a first decaying index alpha_1= 1.29 +/- 0.05 and a first break time
of about 260 s. The decay then flattens to alpha_2=  0.74  +/- 0.02.
After 1450 s the decay is best modelled by a power-law index
alpha_3= 1.15 +/- 0.05.

The very good statistics allows us to observe spectral evolution
in WT data before the first break, with the simple power law photon index
evolving from 2.6 to 2.1 . A spectrum extracted from WT mode data in the
time interval 0.4-1.4 ks can be modelled with an absorbed
power-law with a photon index Gamma= 2.13 +/- 0.05 and best-fitting
absorption column NH = (0.20 +/- 0.01) x10^22 cm^-2, in excess of the 
Galactic
value of 1.9 x 10^20 cm^-2 (Kalberla et al. 2005).

The spectrum extracted from PC data in the time interval 6.1-8 ks
can be modelled with an absorbed power-law, with Gamma = 2.06 +/- 0.09
and a column density of NH = (0.27 +/- 0.03)x10^22 cm^-2.
The observed (unabsorbed) 0.3 -10 keV flux over this time interval is
4.2x10^-11 (6.7x10^-11) erg cm^-2 count^-1.
Uncertainties are given at 90% confidence.

If the light-curve continues to decay with alpha ~1.15, the count rate 24
hours after the burst is estimated to be 0.10 count s^-1, which
corresponds to an observed (unabsorbed) flux of 4.2x10^-12
(6.7x10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00350311.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9238
SUBJECT: GRB 090424: Liverpool Telescope observations
DATE:    09/04/24 23:24:58 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), D. Bersier (Liverpool JMU),
and N. Tanvir (U. Leicester) on behalf of a larger
collaboration report:

We began observing the field of GRB 090424 (Cannizzo et al.
GCN Circ. 9223) with the 2-m Liverpool Telescope at
21:29:47 UT. We clearly detect the optical afterglow
(Cannizzo et al. GCN Circ 9223; Yuan et al. GCN Circ. 9224;
Xin et al. GCN Circ. 9225; Schady et al. GCN Circ. 9234;
Gorosabel et al. GCN Circ. 9236) with r'=19.93  0.03
at a mid epoch of 7.55 hrs post burst from a 6x300 s coadded
exposure. Calibration was performed with respect to nearby
SDSS field stars.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9239
SUBJECT: GRB 090424 optical observations
DATE:    09/04/24 23:40:52 GMT
FROM:    AAVSO GRB Network at AAVSO  <matthewt@aavso.org>

Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports via the AAVSO 
International High Energy Network the following optical observations of 
GRB 090424 (Cannizzo et al., GCN #9223):

A. Oksanen reports the detection of the optical counterpart of GRB 090424 
approximately 6.5 hours post-burst.  Unfiltered observations were made 
using a 0.4-meter RC telescope with an SBIG STL-1001E CCD.  A total of 
sixty, 60-second observations were made having a mid-point time of 
20:45:00 UT on 2009 April 24.  The afterglow was detected with a magnitude 
of 19.1 +/- 0.1 measured relative to the R band magnitude of USNO-A2.0 
1050-06753889 (R=16.3).  Astrometry of the afterglow position yields a 
position of RA: 12h 38m 05.1s, Dec: +16d 50m 15.3s, in agreement with the 
UVOT coordinates given by Cannizzo et al. (GCN #9223).

A jpeg preview of the observation showing the position of the afterglow is 
available at this URL:

http://murtoinen.dyndns.org:8888/ccd/grb/GRB090424/GRB090424-S001-R0XX-Clear.jpg

A detailed report of the observation is available at the following URL:
ftp://ftp.aavso.org/grb/ArtoOksanen_GRB090424_2454946.42162_.txt

A FITS image of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/ArtoOksanen_GRB090424_2454946.42162_.fits

The AAVSO thanks the Curry Foundation for their continued support of the 
AAVSO International High Energy Network.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9240
SUBJECT: GRB 090424 : TAOS optical detection
DATE:    09/04/25 01:27:48 GMT
FROM:    Kuiyun Huang at ASIAA  <ljhuang@asiaa.sinica.edu.tw>

GRB 090424 : TAOS optical detection

Y. Urata, Z.W. Zhang, C.Y. Wen, K.Y. Huang, S.Y. Wang and the TAOS
team

Three 50cm TAOS telescopes, located at Lulin observatory, Taiwan,
started to observe GRB 090424 field (Cannizzo et al.; GCN 9223) at 94s
after the trigger. The optical afterglow (Yuan et al., GCN 9224; Xin
et al. GCN 9225) was clearly detected in images taken by TAOSA (25s
exposure), TAOSB (5s exposure), and TAOSD (1s exposure). Brightness of
the afterglow is about R~13.08 at 94s post the burst. Our R-band
magnitude were calibrated with USNOB red stars.

this message can be cited


GRB_name: GRB090423A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9241
SUBJECT: GRB 090423: Swift/BAT spectral lag results
DATE:    09/04/25 01:47:05 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm@nasa.gov>

H. A. Krimm (CRESST/GSFC/USRA), J. P. Norris (U. Denver), T. N. Ukwatta (GSFC/GWU), 
S. D. Barthelmy (GSFC), P. A. Evans (U. Leicester), N. Gehrels (GSFC), 
M. Stamatikos (GSFC/ORAU)

Using the Swift/BAT data we have completed spectral lag analysis for 
the high redshift burst, GRB 090423 (Krimm et al., GCN 9198).  Using 
16-ms binning on the event data, for the "whole" burst (15 seconds), 
we obtain:

chans 3->1:  0.046 +0.085 -0.058 seconds
chans 3->2:  0.044 +0.070 -0.052 seconds

For the peak 3 seconds of the burst we obtain:

chans 3->1:  0.021 +0.054 -0.032 seconds
chans 3->2:  0.006 +0.046 -0.071 seconds

where the channels are 15-25 keV, 25-50 keV, and 50-100 keV.  The lag 
in each case is consistent with zero, but the 1-sigma error bars are 
roughly as large as the median lag values for long bursts. Thus this 
burst is too dim for us to utilize lags as a discriminant for long vs. 
short.

Given the relatively short duration of this burst, it is informative to 
look at other possible indicators of whether the burst is in fact a 
short burst seen at a large distance.

The calculations below use z=8, which is roughly the average of the 
photometric and spectroscopic redshifts determined for this burst 
(Cucchiara et al., GCN 9213; Olivares et al., GCN 9215; Thoene et al., 
GCN 9216; Perley et al., GCN 9217; Tanvir et al., GCN 9219; 
Fernandez-Soto et al., GRB 9222).

When converted to the rest frame, the T90 values (10.3  1.1 sec, 
Swift/BAT 15-350 keV, Palmer et al., GCN 9204) and (12 sec, Fermi/GBM 
8-1000 keV, Kienlin, GCN Circ. 9229) transform to 1.1  0.1 sec and 
1.3 sec, respectively. However, one must be careful in comparing these 
numbers to the BATSE short-hard burst divide (Kouveliotou et al., 
ApJ 413, L101, 1993).  The  BATSE duration distribution is in the observer frame.  With a typical  redshift of z = 1-2 for BATSE bursts, the dividing 
line between long  and short in the rest frame is 0.7 to 1.0 seconds. 
Thus this burst is on the boundary and toward the long side.

While the duration and lag are consistent with short bursts (with large 
errors), there are other observations which are more consistent with 
GRB 090423 being a long burst in the source frame.

The spectral fits to the BAT data (Palmer et al., GCN 9204) are 
inconclusive as to whether this is a long or short burst. Both the photon 
index, alpha = 0.8 +/- 0.5, and Epeak = 440 keV in the source frame, from 
a cut-off power-law model fit, are consistent with the results for other 
short bursts detected by Swift/BAT.   However, these numbers also fall 
within the distributions for long bursts (Krimm et al., in preparation).

The main argument against this being a short burst is the isotopic energy.
The analysis performed by Amati et al. (GCN 9227) gives the burst 
Eiso=1053 erg and shows that the burst is consistent with the Epeak-Eiso relation for long bursts.  All previously known short bursts are outliers 
to this relation.   The calculated value of Eiso is a factor of > 50 greater than that for most other short bursts.

Furthermore it is questionable whether there would be sufficient time for 
a binary neutron star system to form and inspiral to a merger given the 
very early time interval since the Big Bang implied by z=8 (lookback time 
of ~13 Gyr, corresponding to an age of the universe of 0.6 Gyr).

In conclusion, we can not say if GRB 090423 is short or long.  Its  
duration in the source frame is at the boundary between the two  
classes, the lag analysis is inconclusive, the BAT spectral shape is  
inconclusive, the Amati relationship favors long burst and the merger  
time at such high redshift could be problematic for a short burst  
interpretation.


