# GCN_circulars

GRB_name: GRB100205A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10370
SUBJECT: GRB 100205A: Swift UVOT upper limits
DATE:    10/02/05 17:37:38 GMT
FROM:    Erik Hoversten at Swift/Penn State  <hoversten@astro.psu.edu>

E. A. Hoversten (PSU) and J. L. Racusin (NASA/GSFC) report on behalf
of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100205A
177s after the BAT trigger (Racusin et al., GCN 10361). We do not
detect any source at the enhanced Swift XRT position (Racusin et al.,
GCN 10361) nor at the position of the Gemini-North K-band detection
(Tanvir et al., GCN 10366).  UVOT magnitude 3-sigma upper limits are
reported in the following table:

Filter  T_start  T_stop  Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white     177      327    147      > 20.76
white     177     1533    392      > 21.31
v         665     1580     94      > 18.84
b         763     1162     38      > 19.25
u         335     1311    265      > 20.08


The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.02 mag
(Schlegel et al. 1998). All photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB100205A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10371
SUBJECT: GRB 100205A: Swift-BAT refined analysis
DATE:    10/02/05 18:16:34 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), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), 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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 100205 (trigger #411248)
(Racusin, et al., GCN Circ. 10361).  The BAT ground-calculated position is
RA, Dec = 141.385, 31.740 deg which is 
   RA(J2000)  =  09h 25m 32.5s 
   Dec(J2000) = +31d 44' 23.7" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 80%.
 
The mask-weighted light curve shows a roughly symetric peak starting
at ~T-15 sec, peaking at ~T+5 sec, and ending at ~T+30 sec.
T90 (15-350 keV) is 26.0 +- 8 sec (estimated error including systematics).
 
The time-averaged spectrum from T-12.6 to T+25.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.60 +- 0.25.  The fluence in the 15-150 keV band is 4.0 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+8.12 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/411248/BA/


GRB_name: GRB100113A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10372
SUBJECT: GRB 100113A: Fermi GBM detection
DATE:    10/02/05 19:31:27 GMT
FROM:    Sylvain Guiriec at UAH  <sylvain.guiriec@lpta.in2p3.fr>

Sylvain Guiriec (UAH)
reports on behalf of the Fermi GBM Team:

"At 17:29:24.14 UT on 10 January 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100130A (trigger 286565366 / 100130729).

The on-ground calculated location, using the GBM trigger
data, is RA = 19.89, DEC = -25.21 (J2000 degrees,
equivalent to 01h19m, -25d12'), with an uncertainty
of 2.30 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 51 degrees.

The GBM triggered on a weak and soft peak followed by
a very bright one starting at ~T0+50 s and a weaker one at ~T0+75 s.
The duration (T90) is about 106+/-4 s (8-1000 keV).
The time-averaged spectrum from T0-8 s to T0+96 s is
adequately fit by a power law function with an exponential
high energy cutoff. The power law index is -0.97 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 100.50 +/- 4.77 keV
(Castor C-stat 762 for 488 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(8.21+/-0.30)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+72.7 s in the 8-1000 keV band
is 5.90 +/- 0.23 ph/s/cm^2.

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

------------------------------

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GRB_name: GRB100130B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10373
SUBJECT: GRB 100130B: Fermi GBM detection
DATE:    10/02/05 19:33:39 GMT
FROM:    Sylvain Guiriec at UAH  <sylvain.guiriec@lpta.in2p3.fr>

Sylvain Guiriec (UAH)
reports on behalf of the Fermi GBM Team:

"At 18:38:35.46 UT on 10 January 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100130B (trigger 286569517 / 100130777).

The on-ground calculated location, using the GBM trigger
data, is RA = 77.63, DEC = +20.36 (J2000 degrees,
equivalent to 05h10m, +20d21'), with an uncertainty
of 1.41 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 89 degrees.

The GBM light curve consists of 4 peaks
with a duration (T90) of about 90+/-6 s (8-1000 keV).
The time-averaged spectrum from T0-14 s to T0+89 s is
adequately fit by a power law function with an exponential
high energy cutoff. The power law index is -1.22 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 208.00 +/- 17.10 keV
(Castor C-stat 1074 for 483 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.342 +/- 0.047)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+23.55 s in the 8-1000 keV band
is 3.72 +/- 0.26 ph/s/cm^2.

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


GRB_name: GRB100205A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10374
SUBJECT: GRB 100205A: Gemini-N + NIRI photometry
DATE:    10/02/05 21:18:42 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara (PSU), D. B. Fox (PSU), N. R. Tanvir (U. Leicester),
A. J. Levan (U. Warwick), B. E. Cobb (UC Berkeley), E. Berger 
(Harvard/CfA),
and R. Chornock (Harvard/CfA) report on behalf of a larger collaboration:

We have calibrated the JHK photometry for the candidate Gemini-N + NIRI
afterglow (Tanvir et al., GCN 10366) of GRB 100205A (Racusin et al.,
GCN 10361) against two 2MASS stars in the field.  Converted to AB 
magnitudes we find:

J_AB > 23.37 mag (1-sigma UL)
H_AB     = 23:54 +- 0.22 mag
K_AB     = 21.91 +- 0.20 mag

Thus, based on our photometry we measure a red K-H color, K_AB - H_AB = 
1.6 +- 0.5 mag.
If this red color is due to Lyman-alpha absorption within the H filter 
bandpass, then
this would imply a redshift of 11 <~ z <~ 13.5.   In this connection, we 
note that we are
retracting our earlier claim of a J-band detection (Tanvir et al., GCN 
10366) at the
candidate position.

Lower-redshift solutions with significant local (host) extinction, 
unusual afterglow
colors, or substantial contributions from an underlying host galaxy 
cannot be
excluded at this time.


GRB_name: GRB100205A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10375
SUBJECT: GRB100205A: CFHT z'-band observation
DATE:    10/02/06 13:41:45 GMT
FROM:    Yuji Urata at Nat. Central U.  <urata@astro.ncu.edu.tw>

Y.Urata (NCU), K.Y. Huang (ASIAA), M. Im (SNU)
report on behalf of EAFON:

"We have imaged the field of GRB100205A (Racusin et al. GCN 10361)
using CFHT.  The observation was started at 7:11UT on Feb. 6 (about
26.9 hr after the burst).  The z'-band stacked image shows no source
at the position of the NIR afterglow (Tanvir et al. GCN 10366) down to
z'~24.5."


GRB_name: GRB100206A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10376
SUBJECT: GRB 100206A: Swift detection of a short hard burst
DATE:    10/02/06 13:44:17 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

H. A. Krimm (CRESST/GSFC/USRA), W. H. Baumgartner (GSFC/UMBC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), V. Mangano (INAF-IASFPA),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), M. H. Siegel (PSU), M. A. Stark (PSU),
R. L. C. Starling (U Leicester), E. Troja (NASA/GSFC/ORAU),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 13:30:05 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100206A (trigger=411412).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 47.177, +13.168 which is 
   RA(J2000) = 03h 08m 42s
   Dec(J2000) = +13d 10' 04"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single strong peak 
with a duration of about .3 sec.  The peak count rate
was ~14766 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 13:31:20.0 UT, 74.6 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 47.1617, 13.1579 which
is equivalent to:
   RA(J2000)  = 03h 08m 38.81s
   Dec(J2000) = +13d 09' 28.4"
with an uncertainty of 3.8 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.32e+21 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 78 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
0.38. 

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: GRB100206A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10377
SUBJECT: GRB 100206A: Pre-explosion imaging and host candidate
DATE:    10/02/06 14:29:52 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

A. A. Miller, D. A. Perley, J. S. Bloom, S. B. Cenko (UC Berkeley), and 
P. E. Nugent (LBNL) report:

We co-added 78 archival images from the DeepSky* project at Palomar 
Observatory covering the field of GRB 100206A (Krimm et al., GCN 10376). 
  The images were obtained between 2004-2008 from the Palomar-Quest 
Consortium at the Oschin Schmidt telescope.  The limiting magnitude of 
the stack is approximately R ~ 23 mag.

In the combined image we detect a faint (R = 21.7 +/- 0.3 mag relative 
to nearby USNO catalog stars) extended source, slightly outside the 
current XRT error circle to its northeast.  The approximate (+/- 1") 
coordinates of the source are:

RA = 03:08:39.10, dec = +13:09:29.3  (J2000)

We suggest this as a potential host candidate of the short-hard burst 
and encourage spectroscopic follow-up.

* http://supernova.lbl.gov/~nugent/deepsky.html


GRB_name: GRB100206A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10378
SUBJECT: GRB 100206A: Enhanced Swift-XRT position
DATE:    10/02/06 17:30:38 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 1262 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 100206A, 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 = 47.16225, +13.15708 which is equivalent
to:

RA (J2000): 03h 08m 38.94s
Dec (J2000): +13d 09' 25.5"

with an uncertainty of 3.2 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, MNRAS, 397, 1177).

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


GRB_name: GRB100206A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10379
SUBJECT: GRB 100206A: Swift-BAT refined analysis
DATE:    10/02/06 17:34:23 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), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
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+302 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 100206A (trigger #411412)
(Krimm, et al., GCN Circ. 10376).  The BAT ground-calculated position is
RA, Dec = 47.168, 13.175 deg which is 
   RA(J2000)  =  03h 08m 40.3s 
   Dec(J2000) = +13d 10' 30.3" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 51%.
 
The mask-weighted light curves a single spike starting at ~T+0.0 and
ending at ~T+0.2 sec.  T90 (15-350 keV) is 0.12 +- 0.03 sec (estimated error
including systematics).
 
The time-averaged spectrum from T-0.008 to T+0.124 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.63 +- 0.17.  The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band
is 1.4 +- 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/411412/BA/


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10380
SUBJECT: GRB 100206A: Optical limit
DATE:    10/02/06 18:34:33 GMT
FROM:    Dipankar Bhattacharya at IUCAA  <dipankar@iucaa.ernet.in>

D. Bhattacharya, Vijay Mohan, A.N. Ramaprakash, Chaitanya
Rajarshi (IUCAA) and Kuntal Misra (STScI)report:

We imaged the field of GRB100206A (Krimm et al. GCN 10376,
Goad et al GCN 10378) using the 2-m telescope of the IUCAA
Girawali Observatory. Four 15-min exposures in R-band were
taken on 06 Feb 2010 starting at 15:46 UT.  The stacked
1 hour exposure shows no optical transient to a limiting
magnitude of R ~22.  The extended source reported by Miller
et al (GCN 10377) is however clearly detected.


GRB_name: GRB100206A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10381
SUBJECT: GRB 100206A: Fermi GBM observation
DATE:    10/02/06 19:02:46 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

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

"At 13:30:05.39 UT on 06 February 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100206A (trigger 287155807 / 100206563) which 
was also detected by the SWIFT-BAT (Krimm et al. 2008, GCN 10376). 
The GBM on-ground location is consistent with the Swift position.
 
The angle from the Fermi LAT boresight is 44.7 degrees.

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 GBM light curve shows a single bright peak 
with a duration (T90) of about 0.13 +/- 0.05 s (8-1000 keV). 
The time-averaged spectrum from T0-0.019 s to T0+0.109 s is 
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.18 (+/-0.13) and
the cutoff energy, parameterized as Epeak, is 506 (+68/-53) keV
(Castor C statistic of 569 for 479 d.o.f.)

The event fluence (8-1000 keV) in this time interval is 
(9.3 +/- 0.4)E-07 erg/cm^2. The 0.016-sec peak photon flux measured 
starting from T0-0.003 s in the 8-1000 keV band 
is 31 +/- 2 ph/s/cm^2.

A Band function fits the spectrum equally well (Castor C statistic 
of 565 for 478 d.o.f.) with Epeak= 439 (+73/-60) keV, 
alpha = -0.09 (+0.17/-0.15)and beta = -2.35 (+0.24/-0.43) . 

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


GRB_name: GRB100206A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10382
SUBJECT: GRB 100206A: Swift-XRT refined analysis
DATE:    10/02/06 19:06:13 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans and H. A. Krimm (CRESST/GSFC/USRA) report on behalf of the
Swift-XRT team:

We have analysed 1.3 ks of XRT data for GRB 100206A (Krimm et al. GCN
Circ. 10376), from 82 s to 1.3 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 10378).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.9 (+0.9/-0.7).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.0 (+1.2, -0.9). The
best-fitting absorption column is 3.5 (+5.3, -0.0) x 10^21 cm^-2, in
excess of the Galactic value of 1.3 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 4.6 x 10^-11 (7.4 x 10^-11) erg
cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
1.9, the count rate at T+24 hours will be 1.9 x 10^-7 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.9 x
10^-17 (4.7 x 10^-17) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00411412.

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


GRB_name: GRB100205A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10383
SUBJECT: GRB 100205A: GROND upper limits
DATE:    10/02/06 20:58:37 GMT
FROM:    Ana Nicuesa at TLS Tautenburg  <ana@tls-tautenburg.de>

A. Nicuesa (Tautenburg Obs.), T. Kruehler (MPE), A. Rossi (Tautenburg
Obs.) and J. Greiner (MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 100205A (Swift trigger #411248; Racusin et
al., GCN #10361) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at LaSilla
Observatory (Chile).

Due to cloud coverage, observations started only on 05 Feb. 2010 at
06:37:58 UT, 2.3 h after the burst, and were severely affected by passing
cirrus.

In stacked images with a total integration time of 12 minutes in JHK and
13 minutes in g'r'i'z' we do not detect the NIR afterglow candidate
reported by Tanvir et al. (GCN #10366) down to the following limits, all
in the AB system:

g' > 22.8,
r' > 23.0,
i' > 22.4,
z' > 22.2,
J > 21.0,
H > 20.6 and
K > 20.3

These upper limits have been obtained using SDSS and 2MASS field stars as
reference, and are consistent with the magnitudes reported by
Cucchiara et al. (GCN #10374).


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10384
SUBJECT: GRB 100206A: optical observations from Southern Spain
DATE:    10/02/06 21:34:06 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

S. Guziy, F. J. Aceituno and A. J. Castro-Tirado (IAA-CSIC Granada), on
behalf of a larger collaboration, report:

Following the detection of the short-duration gamma-ray burst GRB 100206A
by Swift/BAT (Krimm et al. GCN Circ. 10376), we have conducted follow-up
observations with the 0.6m TELMA robotic telescope (+ clear filter) at the
BOOTES-2 station in Mlaga and with the 1.5m OSN telescope (+ I-band
filter) at Observatorio de Sierra Nevada in Granada. No optical afterglow
is detected within the Swift/XRT error box (Goad et al., GCN Circ. 10378).
An upper limit of I = 21 is derived from a combined 9 x 150-s I-band image
obtained starting at 18:40 UT (5.2 hr postburst), consistent with the null
result reported by Bhattacharya et al. (GCN Circ. 10380). The candidate
host galaxy reported by Miller et al. (GCN Circ. 10377) is also detected
at the edge of the error box.

This message can be quoted.


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10385
SUBJECT: GRB 100206A, RIMOTS optical upper limits
DATE:    10/02/06 22:03:16 GMT
FROM:    Kazuhiro Noda at Miyazaki U  <kaz1206@astro.miyazaki-u.ac.jp>

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

We have observed the field covering the error circle of
GRB GRB090206A (Swift trigger 411412, GCN 10376, Krimm et al.)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 13:31:14 UT, about 1 min
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.

the upper limits are as follows:
--------------------------------------------------------------
Start(UT) End(UT) Num. of frames Limit (mag.)
--------------------------------------------------------------
13:31:14 13:31:44  1 14.1
13:31:14 14:26:55 29 17.4 
---------------------------------------------------------------


GRB_name: GRB100206A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10386
SUBJECT: GRB 100206A: WHT candidate afterglow
DATE:    10/02/06 23:56:02 GMT
FROM:    Andrew Levan at U.of Leicester  <A.J.Levan@warwick.ac.uk>

A.J. Levan (U. Warwick), N.R. Tanvir, K. Wiersema (U. Leicester)
M. Niederste-Ostholt (Cambridge), D. Malesani, G. Leloudas
(DARK/NBI)  D. Xu (WIS & DARK/NBI) report for a larger collaboration:

"We observed the localization of GRB 100206A (Krimm et al. GCN 10376)
with the WHT beginning at 20:33 UT, approximately 7 hours after the
burst. Observations were obtained in the i and z bands with exposures
of 2000 and 2400s respectively.

Inside the refined XRT error circle (Goad et al. GCN 10378), we
detect a faint source in both the i and z-bands.  The location of
the source is:

RA(J2000) = 03:08:38.99
DEC(J2000) = 13:09:22.7

With an uncertainty of approximately 0.5" in each axis. We consider
this to be a candidate afterglow of GRB 100206A, however cannot
currently place any constraints on variability of the source.

Further observations are planned."


GRB_name: GRB100206A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10387
SUBJECT: GRB 100206A: NOT NIR observations
DATE:    10/02/06 23:56:28 GMT
FROM:    Giorgos Leloudas at Dark Cosmology Centre  <giorgos@dark-cosmology.dk>

G. Leloudas (DARK/NBI), D. Xu (WIS and DARK/NBI), D. Malesani (DARK/ 
NBI), A. J. Levan (U. Warwick), P. Jakobsson (Univ. Iceland), A. A.  
Djupvik (NOT), report, on behalf of a larger collaboration:

We observed the field of GRB 100206A (Krimm et al., GCN 10376) with  
the NOT equipped with NOTCam.

Observations were carried out in the Ks-filter (6x9x60 s) starting at  
20h24 UT, i.e. 6.9 hr after the GRB.

Inside the enhanced XRT position (Goad et al., GCN 10378) we do not  
detect any object down to a limiting magnitude > 19.7 (based on the  
nearby 2MASS star 03083760+1308461).

The extended object reported by Miller et al. (GCN 10377) is clearly  
detected at  Ks ~ 16.4.


GRB_name: GRB100206A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10388
SUBJECT: GRB100206: MITSuME optical upper limits
DATE:    10/02/07 02:15:59 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>

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

We observed the field of GRB 100206A (Krimm et al. GCN 10376)
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 2010-02-06 13:31:10 UT (65s after the
burst). We did not find any new point source in the XRT error
circle in all the three bands.

Three sigma upper limits of the OT are listed below. We used
GSC2.3 catalog for flux calibration.

PDAY     MID-UT    T-EXP    g'     Rc     Ic
---------------------------------------------------
0.00422  13:36:10   480.0 >19.0  >19.0  >17.9
0.02166  14:01:17  2940.0 >19.8  >19.8  >18.7
---------------------------------------------------


GRB_name: GRB100206A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10389
SUBJECT: GRB 100206A - Keck/LRIS Spectroscopy
DATE:    10/02/07 06:49:28 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko, J. S. Bloom, D. A. Perley, B. E. Cobb, A. N. Morgan, and A.
A. Miller, Maryam Modjaz (UC Berkeley) and B. James (DARK) report on
behalf of a larger collaboration:

We have obtained spectra of the likely host galaxy (Miller et al., GCN
10377) and afterglow (Levan et al., GCN 10386) of the short-hard
GRB100206A (Krimm et al, GCN 10376) with the Low Resolution Imaging
Spectrometer mounted on the 10-m Keck I telescope.  Observations began at
06:17 UT on 7 February (~ 16.8 hours after the burst) and cover the
wavelength range from approximately 3500 - 10000 A.

At the location of the candidate host galaxy, we detect a strongly red
continuum consistent with the published photometry (Leloudas et al., GCN
10387).  We detect strong, clearly resolved emission lines from H-alpha
and [NII] at a redshift of z = 0.41.  No other obvious lines are visible
over spectral range in our preliminary reduction.  The lack of H-beta,
coupled with the red spectrum and colors, suggest a relatively dusty
environment.  At this redshift, the projected offset of ~ 6.8" from the
candidate afterglow corresponds to a distance of ~ 35 kpc.

No obvious trace is visible at the location of the afterglow.

Observations and reduction are ongoing.


GRB_name: GRB100206A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10390
SUBJECT: GRB 100206A: PAIRITEL Photometry of Host Candidate
DATE:    10/02/07 11:00:55 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

A. N. Morgan, B. E. Cobb,  J. S. Bloom, S. B. Cenko, D. A. Perley, A.
A. Miller, M. Modjaz, C. R. Klein (UC Berkeley), report:

We have imaged the field of the short-hard GRB 100206A (Krimm et al.,
GCN 10376)  with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona.
Observations began at 2010-02-07 02:37:50 UT (~13.1 hours after the
burst).  The potential host galaxy (Miller et al., GCN 10377) is
clearly detected in mosaics taken simultaneously in the J, H, and Ks
filters (effective exposure time of 2293 seconds).  The preliminary
photometry yields:

exp(s)  filt    mag
==============================
2293    J       18.35 +/- 0.07
2293    H       17.55 +/- 0.08
2293    Ks      16.56 +/- 0.08
==============================

A preliminary estimate of the metallicity from the Halpha and [N II]
line ratios suggest a super-solar metallicity (~1.5 solar metallicity,
using Asplund 2009 for Solar oxygen abundance). At a redshift of z =
0.41 (Cenko et al., GCN 10389), and assuming a Lambda-CDM cosmology
with H_0=74 km/s/Mpc, Omega_M=0.27 and Omega_Lambda=0.73, we calculate
the distance modulus to be 41.65 mag, which implies a rest-frame
H-band magnitude of about -25 mag. This extreme luminosity, coupled
with what appears to be strong optical reddening (Cenko et al., GCN
10389) suggests that this galaxy is a luminous infrared galaxy
(LIRG/ULIRG). While the physical connection to GRB 100206A has not
been definitively established, the probability of a chance coincidence
of such a galaxy with a SHB is low, providing an a posterori argument
for a physical connection.

All magnitudes given in the Vega system, calibrated to 2MASS.  No
correction for Galactic extinction has been made to the above reported
values.


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10391
SUBJECT: GRB 100206A: MASTER-Net  optical alert observations 
DATE:    10/02/07 13:24:10 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

V.Yurkov, S.Sergienko 
Blagoveschensk Educational State University, Blagoveschensk


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

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


V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov 
Ural State University, Kourovka


K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok
Irkutsk State University


MASTER  robotic telescope (MASTER-Net: http://observ.pereplet.ru, 200
mm, FOV=8 square degrees (testing mode)) and  Very Wide Field Camera (D=50 mm, 
1000 square  degrees, 11 Mpx, 36" per pix, mounted on telescope) located at 
Blagoveschensk   was responted to the  GRB 100206A (Swift BAT  alert, 
TRIGGER_NUM: 411412, Krimm et al, GCN CIRC 10376) 73 sec after first 
Notice time and 90 s after the GRB time.
Unfortunatelly, the main telescope camera was not operating due to 
technical problem at this time.

We have a number images with 5 s exposition from Very Wide Field Camera.
The image limit from Very Wide Filed Camera ~11.5.
trees)  is available  at 
http://observ.pereplet.ru/images/GRB100206A/grb100206A.png 
.

There is no OT brighter 11.5.

The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100206A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10392
SUBJECT: GRB 100206A: YNAO-GMG observations
DATE:    10/02/07 13:26:10 GMT
FROM:    Jirong Mao at INAF-OAB  <jirong.mao@brera.inaf.it>

J. Mao (YNAO & INAF-OAB), D. Wang  and J. Bai (YNAO) report on behalf of 
the GMG group:
 
Starting 14h 44m UT, after more than 1 hour of the trigger, we observed 
the field of GRB 100206A (Krimm et al., GCN 10376) with one 2.4-m 
telescope located at Gao-Mei-Gu (GMG). We did not see the afterglow in 
the R-band image with exposure time 20 min. However, the nearby 
galaxy(Miller et al. GCN 10377) were clearly detected, the magnitude is 
about R ~ 21.5 referenced to one USNO star.
 
This message might be cited.


GRB_name: GRB100131A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10393
SUBJECT: GRB 100131A: MASTER-Net  optical alert observations 
DATE:    10/02/07 13:47:58 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

V.Yurkov, S.Sergienko Blagoveschensk Educational State University, 
Blagoveschensk


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

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


V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov Ural State University, Kourovka


K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok
Irkutsk State University


MASTER  robotic telescope (MASTER-Net: http://observ.pereplet.ru, 200
mm, FOV=8 square degrees (testing mode)) and  Very Wide Field Camera (D=50 mm, 
1000 square  degrees, 11 Mpx, 36" per pix, mounted on telescope) located at 
Blagoveschensk   was responted to the  GRB 100131A (Fermi GBM  alert,
  Goldstein et al, GCN CIRC 10358) 76 sec after first Notice 
time and 93 s after the GRB time.
The center FOV of the main telescope correspond to first alert 
imformation:

  RA=107.420+-3         DEC=+3.730+-3

The limit of the main telescope images is aboute 15 mag (unfiltered).


We have a number images with 5 s exposition from Very Wide Field Camera.
The image limit from Very Wide Filed Camera ~10 mag.
There is now OT in our images inside Fermi error box (A. Goldstein, GCN 
CIRC 10358) brighter 10 mag.

The imege  is available  at 
http://observ.pereplet.ru/images/GRB100131A/grb100131A.jpg .
The circles correspond to  1sigma + systematic Fermi error box, and
  3sigma+systematic error box.
The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100206A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10394
SUBJECT: GRB 100206A: Swift/UVOT Upper Limits
DATE:    10/02/07 17:03:04 GMT
FROM:    Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and H.A. Krimm (CRESST/GSFC/USRA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100206A
78 s after the BAT trigger (Krimm et al., GCN Circ. 10376).
No optical afterglow consistent with the refined XRT position
(Goad et al., GCN Circ. 10378) or the candidate optical afterglow
position (Levan et al., GCN Circ. 10386)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC)
exposures and subsequent exposures are:

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

white_FC            78          228          147         >20.5
u_FC               290          540          246         >20.1
white               78         7046          647         >21.4
v                  619         7457          553         >20.1
b                  545        13655         1223         >21.2
u                  290        12756         1464         >20.5
w1                 668         7866          510         >20.7

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.38 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10395
SUBJECT: GRB 100206A: Gemini-North observations
DATE:    10/02/07 17:13:40 GMT
FROM:    Edo Berger at Harvard  <eberger@cfa.harvard.edu>

E. Berger, R. Chornock (Harvard), N. Tanvir (U. Leicester), A.J. Levan
(U. Warwick), D. Fox, A. Cucchiara (PSU), A. Fruchter and J. Graham
(STScI) report on behalf of a larger collaboration:

"We observed the field of the short GRB 100206A (GCN #10376) with GMOS
on the Gemini-North 8-m telescope starting on 2010 Feb 7.215 (15.7
hours after the burst).  Observations were obtained in the i- and
z-band filters for a total of 1200 sec in each filter.  Inside the
refined XRT error circle (GCN #10378) we detect the candidate optical
afterglow detected with the WHT (GCN #10386).  Within the photometric
uncertainties the source does not appear to fade in either filter
between the two observation (7 and 15.7 hours) and it is thus unlikely
to be the optical afterglow.  However, since the source is located
within the XRT error circle we consider it to be a potential host
galaxy, likely at a higher redshift than the bright galaxy at z=0.41
located just outside the error circle (GCN #10389)."


GRB_name: GRB100206A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10396
SUBJECT: GRB 100206A: GROND upper limits
DATE:    10/02/07 17:40:07 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

A. Nicuesa (Tautenburg Obs.), T. Kruehler (MPE), S. Klose (Tautenburg
Obs.) and J. Greiner (MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 100206A (Swift trigger #411412; Krimm et
al., GCN #10376) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at LaSilla
Observatory (Chile).

Observations started on 7 February 2010 at 00:31 UT, 11 hours after the GRB
trigger, and were performed at high airmass and poor seeing conditions.

In stacked images with a total integration time of 40 minutes in JHK and
50 minutes in g'r'i'z' we do not detect the object reported by Levan et
al. (GCN #10386) and Berger et al. (GCN #10395) down to the following
limits, all in the AB system:

g' > 23.2,
r' > 23.4,
i' > 22.4,
z' > 22.2,
J > 21.2 ,
H > 20.7 and
K > 20.0

These upper limits have been obtained using the GROND zeropoints and 2MASS
field stars as reference. The nearby object (Miller et al., GCN#10377,
Bhattacharya et al., GCN#10380, Guziy et al., GCN#10384, Leloudas et al.,
GCN#10387, Cenko et al., GCN# 10389, Morgan et al., GCN#10390, Mao et al.
#10392) is detected in all seven bands.


GRB_name: GRB100205B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10397
SUBJECT: GRB 100205B: Fermi GBM detection
DATE:    10/02/07 18:20:33 GMT
FROM:    David Gruber at MPE  <dgruber@mpe.mpg.de>

David Gruber (MPE)
reports on behalf of the Fermi GBM Team:

"At 11:45:38.26 UT on 05 February 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100205B (trigger 287063140 / 100205490).

The on-ground calculated location, using the GBM trigger
data, is RA = 133.9, DEC = -23.0 (J2000 degrees,
equivalent to 08h 55m, 23d 00'), with an uncertainty
of 8.2 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 102 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 13.6 +/- 1.6s (8-1000 keV).
The time-averaged spectrum from T0-1.024s to T0+7.168 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -0.47 (+0.20/-0.19) and
the cutoff energy, parameterized as Epeak, is 124.20 (+16.0/-12.2)keV
(c-stat 468.61 for 349 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.410 +/-  0.082)E-6 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0 in the 8-1000 keV band
is 2.98 +/- 0.22 ph/s/cm^2.

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


GRB_name: GRB100205A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10398
SUBJECT: GRB 100205A: BOAO/LOAO zYJK observation 
DATE:    10/02/09 14:50:50 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, Y. Jeon, W. Park (CEOU/Seoul National Univ),
  H.-I. Sung (KASI) and Y. Urata (NCU) on behalf of EAFON team.

   We observed the GRB100205A (GCN 10361 Racusin et al.)
  with J and K-band using KASINICS instrument on the 1.8m telescope
  at the Bohyunsan Optical Astronomy Observatory (BOAO), Korea,
  starting from 2010-02-05, 17:28:13 UT. We also observed the GRB
  with z and Y filters using the LOAO 1-m telescope,
  starting from 2010-02-05, 10:37:51 UT.

   We do not detect the afterglow at the reported position
  (GCN 10361.; GCN 10366, Tanvir et al.) in any of the bands
  with the upper limits summarized below.
   Our non-detection in K suggests that the afterglow candidate
  faded since the report of the K-band detection (GCN 10366;
  GCN 10374 Cucchiara et al.), confirming that it is
  an afterglow. The values for J and K-bands are preliminary,
  and we are refining the photometry. The data analysis of
  the 2nd night follow-up observation (z,Y) is on-going.

        Filter            z      Y      J       K
   -------------------------------------------------
   3-sigma limit (AB)   22.3   20.8   22.3    22.5
   mid-point(UT,hh:mm)  12:11  11:07  17:43   19:01

   We thank the LOAO operator, J. Yoon for his assistance for this
   observation.


GRB_name: GRB100205A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10399
SUBJECT: GRB 100205A: Keck limits on an underlying host galaxy
DATE:    10/02/10 13:06:10 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, J. S. Bloom, S. B. Cenko, B. E. Cobb, A. N. Morgan, A. A. 
Miller, and C. R. Klein (UC Berkeley) report:

We conducted a deep optical imaging integration on the field of GRB 
100205A (Racusin et al., GCN 10361) using LRIS on the Keck I 10m 
telescope starting at 09:48 UT on 2010 Feb 7.  We integrated for a total 
exposure time of 4000 seconds in g-band and 3770 seconds in R-band 
simultaneously under clear skies but variable and generally poor seeing 
conditions (1.5 arcsec average).  The mid-point of the integration was 
at 10:28 UT.

We detect no source at the position of the putative infrared afterglow 
(Tanvir et al., GCN 10366).  Calibrating relative to USNOB1.0, we 
measure limiting magnitudes (3-sigma) of:

R > 26.7
g > 26.6

as measured at the afterglow location.  A faint source is marginally 
detected (<2 sigma) in R-band only at the northwestern edge of the XRT 
error circle (Evans et al., GCN 10367), not consistent with the position 
of the infrared afterglow.

We also stacked the R-band and g-band images together to create a 
white-light composite image.  There is no significant detection in this 
image, with an approximate limiting magnitude of White > 27 mag.

All properties of this GRB are consistent with it being at high redshift:

* Lack of optical detection starting at early times (e.g. Malesani et 
al., GCN 10362; Updike et al., GCN 10364; Cobb et al, GCN 10365)
* An apparently fading afterglow candidate detected only in H- and 
K-bands (Cucchiara et al., GCN 10374; Im et al., GCN 10398)
* Limited X-ray absorption: excess N_H(z=0) = 7(+6/-5) x 10^20 cm^-2 
(Starling and Racusin, GCN 10369), generally suggestive of higher 
redshift (Grupe et al. 2007, AJ 133:2216G) and inconsistent with the 
alternative hypothesis of a large extinction column at low redshift for 
typical values of A_V/N_H.
* Lack of host galaxy to deep limits (Perley et al. 2009, AJ 138:1690)

As mentioned by Cucchiara et al., the implied redshift of this GRB if 
the red H-K color is due to Lyman-alpha absorption would be z ~ 11-13. 
However, significant dust absorption at intermediate redshift (e.g., 
A_V~3 mag at z~4) is still generally consistent with the available data, 
and unfortunately the X-ray afterglow is too faint to impose meaningful 
constraints on extinction in the K-band during the Gemini observation.

An image of the field is posted to:
http://lyra.berkeley.edu/~dperley/100205a/100205a_keck_gR.png

We encourage continued deep infrared follow-up of the field.


GRB_name: GRB091127A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10400
SUBJECT: GRB 091127: Detection of a Supernova
DATE:    10/02/11 03:45:12 GMT
FROM:    Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>

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

We have obtained multiple epochs of imaging of the field of GRB 091127
(Troja et al., GCN 10191) using the Gemini Multi-Object Spectrograph 
(GMOS) on the 8 m Gemini South telescope and the ANDICAM instrument
on the 1.3m telescope at CTIO.  For the first ~10 days post-burst, the 
optical afterglow of the GRB (e.g. Smith et al., GCN 10192, Immler et al., 
GCN 10193, Cobb, GCN 10244) dominates the burst's optical emissions. 
After 10 days post-burst, however, we find evidence of an additional 
component of light which rises and then fades, and we consider this to be 
due to an underlying SN related to this GRB.

The rise and decay characteristics of this GRB-SN are globally similar to 
those of the prototypical GRB-SN, SN1998bw.  The SN reaches peak 
brightness at approximately 30 days post-burst, which is consistent with 
the rise-time  expected for a GRB-SN at redshift z=0.49 (Cucchiara et 
al., GCN 10202 & Thoene et al., GCN 10233). The observed peak magnitude 
of the SN (and any underlying contribution from a host galaxy) is I~21.7. 
Correcting for a small amount of Galactic reddening (A_V=0.125) and 
assuming little or no host-galaxy reddening (which is consistent with the 
observations of the optical afterglow of the GRB), the absolute magnitude 
of this GRB-SN is V~-20.5.

Observations and analysis of this GRB-SN are ongoing.


GRB_name: GRB100212A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10401
SUBJECT: GRB 100212A: Swift detection of a burst
DATE:    10/02/12 14:25:34 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

D. Grupe (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
V. D'Elia (ASDC), P. A. Evans (U Leicester), J. M. Gelbord (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
O. M. Littlejohns (U Leicester), V. Mangano (INAF-IASFPA),
J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
M. Perri (ASDC), P. Romano (INAF-IASFPA),
B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU),
R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 14:07:22 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100212A (trigger=412081).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 356.462, +49.497 which is 
   RA(J2000) = 23h 45m 51s
   Dec(J2000) = +49d 29' 50"
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 2 sec.  The peak count rate
was ~5500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 14:08:19.8 UT, 57.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 356.41805, 49.49497 which
is equivalent to:
   RA(J2000)  = 23h 45m 40.33s
   Dec(J2000) = +49d 29' 41.9"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 103 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 (1.3e+21
cm^-2, Kalberla et al. 2005), with an excess column of 2.5
(+1.73/-1.52) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 1.39e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
280 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 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.18. 

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: GRB100212A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10402
SUBJECT: GRB 100212A: candidate optical afterglow
DATE:    10/02/12 21:32:58 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. Malesani, G. Leloudas, J. P. U. Fynbo (DARK/NBI), D. Xu (WIS and 
DARK/NBI), P. Jakobsson (Univ. Iceland), A. Somero, S. Katajainen 
(Tuorla Obs.), T. Pursimo (NOT), report on behalf of a larger collaboration:

We observed the field of GRB 100212A (Grupe et al., GCN 10401) with the 
NOT equipped with ALFOSC. Observations started on Feb 12.841 UT (6.05 hr 
after the GRB), in the R band.

Close to the refined XRT error circle (as reported in the SPER web page 
http://www.swift.ac.uk/sper/index.php at 21:30 UT), we detect a source 
which is not visible in the DSS. Its coordinates are (J2000):

RA = 23:45:40.23
Dec = +49:29:40.7

The object is 2.5" away from the centre of the XRT position, currently 
reported to have a 2.2" error radius.

The R-band magnitude of the source is R = 20.3 assuming R = 17.3 for the 
USNO star at RA = 23:45:42.93, Dec = +49:30:29.3. The source looks 
pointlike under a seeing of 1" and is clearly brighter than other 
closeby objects visible in the DSS.

We suggest this object to be the afterglow of GRB 100212A.


GRB_name: GRB100212A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10403
SUBJECT: GRB 100212A: Enhanced Swift-XRT position
DATE:    10/02/13 03:11:08 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 699 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 100212A, 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 = 356.41830, +49.49432 which is equivalent
to:

RA (J2000): 23h 45m 40.39s
Dec (J2000): +49d 29' 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) and Evans
et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB100212A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10404
SUBJECT: GRB 100212A: Swift-BAT refined analysis
DATE:    10/02/13 03:44:18 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),
D. Grupe (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 100212A (trigger #412081)
(Grupe, et al., GCN Circ. 10401).  The BAT ground-calculated position is
RA, Dec = 356.445, 49.492 deg, which is 
   RA(J2000)  =  23h 45m 46.9s 
   Dec(J2000) = +49d 29' 30.5" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 86%.
 
The mask-weighted light curve shows multiple peaks.  The main peak starts
with weak emission at ~T-45 sec with the peak at ~T+0.2 sec and ends 
at ~T+30 sec.  A second peak starts at ~T+75 and ends at ~T+135 sec.
T90 (15-350 keV) is 136 +- 14 sec (estimated error including systematics).
 
The time-averaged spectrum from T-4.8 to T+134.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.20 +- 0.22.  The fluence in the 15-150 keV band is 9.1 +- 1.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.34 sec in the 15-150 keV band
is 2.2 +- 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/412081/BA/


GRB_name: GRB100212A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10405
SUBJECT: GRB 100212A: Swift XRT refined analysis
DATE:    10/02/13 04:52:41 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

D. Grupe (PSU) reports on behalf of the Swift-XRT team:

We have analyzed 1.9 ks of XRT data for GRB 100212A (Grupe et al.
GCN Circ. 10401), from 64 s to 7 ks after the BAT trigger. The
data comprise 409 s in Windowed Timing (WT) mode with the remainder
  in Photon Counting (PC) mode. The enhanced XRT position for this
  burst was given by Osborne et al. (GCN. Circ 10403).

The light curve is complicated displaying several strong flares up
to 700s after the burst. The underlying afterglow light curve
suggests a step decay slope of alpha=2.89+/-0.09. However, the data
of the second orbit indicate the beginning of the plateau phase with
a significantly flatter decay slope. Predictions of the further
development of the X-ray light curve are not reliable at this point.

A spectrum formed from the WT mode data can be fitted with an
absorbed power-law with a photon spectral index of 2.03 (+/-0.03).
  The best-fitting absorption column is 1.97 (+/-0.08) x 10^21 cm^-2,
   in excess of the Galactic value of 1.3 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 3.8 x 10^-11
   (5.6 x 10^-11) ergs cm^-2 count^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00412081.

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


GRB_name: GRB100212A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10406
SUBJECT: GRB 100212A: Fermi GBM detection
DATE:    10/02/13 05:36:10 GMT
FROM:    Sylvain Guiriec at UAH  <sylvain.guiriec@lpta.in2p3.fr>

Sylvain Guiriec (UAH) and Dave Tierney (UCD/MPE)
report on behalf of the Fermi GBM Team:

"At 14:07:29 UT on 12 February 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100212A (trigger 287676444 / 100212588).

This GRB has also been detected independently with Swift/BAT and the
GBM location is consistent with the Swift/XRT location within the error bars

(Grupe et al. GCN Circ. 10401).

The angle from the Fermi LAT boresight is 15 degrees.

The GRB duration (T90) is about 2.30+/-0.14 s (8-1000 keV).
The time-averaged spectrum from T0-0.51 s to T0+0.26 s is
adequately fit by a power law with an index of -1.62+/-0.06
(Castor C-stat 394 for 363 d.o.f.).
It is also adequately fit by a power law function with an exponential
high energy cutoff. The power law index is -1.15 +/- 0.20 and
the cutoff energy, parameterized as Epeak, is 159.30 +/- 45.10 keV
(Castor C-stat 389 for 362 d.o.f.).

The event fluence (8-1000 keV) in the T90 time interval is
(3.81+/-0.06)E-7 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.7 s in the 8-1000 keV band is 3.16 +/- 0.22 ph/s/cm^2.

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


GRB_name: GRB100212A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10407
SUBJECT: GRB 100212A: LOAO R-band Detection/V-band Observation 
DATE:    10/02/13 11:04:10 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

   M. Im (CEOU/Seoul National Univ) and Y. Urata (NCU)
  on behalf of EAFON team.

   We observed GRB100212A (Grupe et al. GCN 10401) in R and V
  using the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by
  the Korea Astronomy Space Science Institute.
   The observation started at Feb. 13, 02:05:14 UT, about 12 hours
  after the BAT trigger.

   The stacked R-band image shows a marginal detection of
  the afterglow with R ~ 22.5 +- 0.2 mag, at the location reported by
  Malesani et al. (GCN 10402).  The mid-point for the R-band imaging
  is 02:17:36 UT. The object does not appear in a stacked V-band
  image, which was taken right after the R-band observation.
   Our obseravation shows that the afterglow candidate faded
  significantly since the report by Malesani et al. (GCN 10402),
  confirming that this is indeed a GRB afterglow.
   The photometry was calibrated against the USNO star (GCN 10402).

   We thank the LOAO operator, J. Yoon for her assistance of this
  observation.


GRB_name: GRB120212A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10408
SUBJECT: Swift/UVOT observations of GRB120212A
DATE:    10/02/13 15:32:09 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <mdp@mssl.ucl.ac.uk>

M. De Pasquale (MSSL/UCL) and D. Grupe (PSU) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100212A
68 s after the BAT trigger (Grupe et al., GCN Circ. 10401) with
the finding chart in the white filter.
No optical afterglow is detected within the enhanced XRT error circle
position (Osborne et al., GCN Circ 10403) in the initial UVOT exposure
and in all other summed exposures at 3 sigma level. The optical source
detected by NOT (Malesani et al, GCN circ 10402) is not detected either
at 3 sigma level.

Preliminary 3-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            68          218          147         >20.6
u_FC               281          530          246         >19.8
white               68         1181          353         >21.2
v                  610         1231           78         >18.7
b                  536         1156           58         >19.5
u                  281         1304          304         >19.8
w1                 660         1280           78         >19.2
m2                 635         1255           78         >19.3
w2                 586         1206           78         >19.6

The values quoted above are not corrected for the strong Galactic 
extinction due to the reddening of E(B-V) = 0.18 in the direction of the 
burst (Schlegel et al. 1998).


GRB_name: GRB100212A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10409
SUBJECT: Swift/UVOT observations of GRB100212A - correction of the name of the burst
DATE:    10/02/13 15:37:53 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <mdp@mssl.ucl.ac.uk>

The previous GCN 10408 dealt with GRB100212A, not GRB120212A as 
erroneously written. I apologize for the mistake.


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10410
SUBJECT: GRB 100206A:  Second epoch Gemini-north observations and afterglow limits
DATE:    10/02/13 21:24:47 GMT
FROM:    Edo Berger at Harvard  <eberger@cfa.harvard.edu>

E. Berger and R. Chornock (Harvard) report on behalf of a larger 
collaboration:

"We obtained a second epoch of i-band imaging of the short GRB 100206A
(GCN 10376) with GMOS on the Gemini-North 8-m telescope starting on
2010 Feb 12.28 UT.  Digital image subtraction of the new observation
relative to our previous i-band epoch from 2010 Feb 7.23 UT (GCN
10395) using the ISIS software package does not reveal any fading
sources to a 3-sigma limit of i>24.7 mag within the XRT error circle
(GCN 10378), in coincidence with the nearby bright galaxy at z=0.41
(GCN 10389), or in coincidence with the nearby fainter galaxy (GCNs
10386,10395).  We therefore place a limit of i>24.7 mag on the
brightness of the optical afterglow at 15.7 hours after the burst."


GRB_name: GRB100213A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10411
SUBJECT: GRB 100213A: Swift detection of a burst
DATE:    10/02/13 22:44:16 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

D. Grupe (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD),
D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC),
B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU),
M. C. Stroh (PSU), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report
on behalf of the Swift Team:

At 22:27:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100213A (trigger=412217).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 349.428, +43.383 which is 
   RA(J2000)  =  23h 17m 43s
   Dec(J2000) = +43d 23' 00"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two main spikes
with a total duration of about 4 sec (we can not reject a short burst). 
The peak count rate was ~6000 counts/sec (15-350 keV), at ~2 sec
after the trigger. 

The XRT began observing the field at 22:29:00.8 UT, 72.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 349.3917, 43.3796 which
is equivalent to:
   RA(J2000)  = 23h 17m 34.01s
   Dec(J2000) = +43d 22' 46.4"
with an uncertainty of 3.2 arcseconds (radius, 90% containment). This
location is 95 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.11e+21 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 76 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 16% 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
0.31. 

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: GRB100213B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10412
SUBJECT: GRB 100213B: Swift detection of a burst
DATE:    10/02/13 23:12:15 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

L. Vetere (PSU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
J. M. Gelbord (PSU), D. Grupe (PSU), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), C. Pagani (PSU), D. M. Palmer (LANL),
T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU), M. C. Stroh (PSU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 22:58:34 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100213B (trigger=412220).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 124.338, +43.455 which is 
   RA(J2000)  =  08h 17m 21s
   Dec(J2000) = +43d 27' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a FRED-like pulse
structure with a duration of about 30 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 23:01:03.7 UT, 149.5 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 124.2858, +43.4473 which is equivalent to:
   RA(J2000)  = 08h 17m 08.59s
   Dec(J2000) = +43d 26' 50.2"
with an uncertainty of 5.2 arcseconds (radius, 90% containment). 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 1.75e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of  77 seconds with the White filter
starting 157 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 about 20.5 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
0.08. 

Burst Advocate for this burst is L. Vetere (vetere 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: GRB100213B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10413
SUBJECT: GRB 100213B: NOT optical observations
DATE:    10/02/14 00:44:21 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. Malesani (DARK/NBI), N.R. Tanvir (Univ. Leicester), D. Xu (WIS, 
DARK/NBI), G. Leloudas (DARK/NBI), P. Jakobsson (Univ. Iceland), A. 
Somero, and S. Katajainen (Tuorla Obs.), report on behalf of a larger 
collaboration:

We observed the field of GRB 100213B (Vetere et al., GCN 10412) with the 
NOT equipped with ALFOSC. Due to adverse weather, we could only obtain 
one 5-min R-band exposure, starting on Feb 13.970 UT (19 min after the GRB).

We  find an object with R ~ 21.5 located just outside the edge of the 
XRT error circle, at coordinates RA = 08:17:07.97, Dec = +43:26:54.6. 
This location is 8 arcsec away of the X-ray position, which has a 
reported error radius of 5.2" (Vetere et al., GCN 10412). The object 
seems elongated in our image. However, it is not visible in the SDSS 
data of this field, and may therefore be the afterglow of GRB 100213B.

Inside the XRT error circle, there is also a possible source close to 
our image detection limit (R ~ 22.2), at coordinates RA = 08:17:08.48, 
Dec = +43:26:50.3 (0.8" uncertainty). Given the low S/N, the reality of 
this source cannot be confirmed.

Further observations are encouraged. The NOT may attempt again later 
tonight depending on the weather conditions.


GRB_name: GRB100213A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10414
SUBJECT: GRB 100213A: Swift XRT refined analysis
DATE:    10/02/14 05:02:10 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

D. Grupe (PSU) reports on behalf of the Swift-XRT team:

We have analyzed 274 s of XRT data for GRB 100213A (Grupe et al.
GCN Circ. 10411), from 86 s to 361 s after the BAT trigger. The
data are entirely in  Photon Counting (PC) mode. At this point only
data of the first orbit are available. Further observations have
been delayed due to the detection of GRB 100213B (Vetere et al., GCN
Circ. 10412). Therefore no prediction of the future light curve is
possible at this time.

A spectrum formed from the PC mode data can be fitted with an
absorbed  power-law with a photon spectral index of 2.04
(+0.45, -0.56) with the absorption column density fixed to 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  4.5 x 10^-11
(5.9 x 10^-11) erg cm^-2 count^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00412217.

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


GRB_name: GRB100213A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10415
SUBJECT: GRB 100213A: SARA observations
DATE:    10/02/14 05:05:29 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike (Clemson University), Gary D. Henson (ETSU), and Dieter H.
Hartmann (Clemson University) report:

We observed the field of GRB 100213A (Grupe et al., GCN 10411) with the
0.9m SARA telescope located on Kitt Peak in Arizona beginning 4 hours and
11 minutes after the trigger at high airmass under good conditions.  In 20
minutes of stacked exposures, we detect no new sources in the XRT error
circle down to a limiting magnitude of R ~ 20 (as compared to USNO B1.0
field stars).


GRB_name: GRB100213B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10416
SUBJECT: GRB 100213B: Swift XRT refined analysis 
DATE:    10/02/14 05:07:53 GMT
FROM:    Loredana Vetere at PSU  <vetere@astro.psu.edu>

L. Vetere (PSU) reports on behalf of the Swift-XRT team:

We have analysed 1.7 ks of XRT data for GRB 100213B (Vetere et al.
GCN Circ. 10412), from 155 s to 5.7 ks after the BAT trigger. The
data comprise 500 s in Windowed Timing (WT) mode with the remainder
in Photon Counting (PC) mode. Using  1.2ks of XRT Photon Counting
mode data we find a refined XRT position: RA, Dec = 124.28384,
43.44683 which is equivalent to:

RA (J2000): 08h 17m 08.12s
Dec (J2000): +43d 26' 48.6"

with an uncertainty of 4.9 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.06 (+0.10, -0.08). A spectrum formed from the WT
mode data can be fitted with an absorbed power-law with a photon
spectral index of 1.47 (+/-0.12). The best-fitting absorption column
is 1.3 (+0.4, -0.3) x 10^21 cm^-2, in excess of the Galactic value of
5.9 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 (5.6 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index
of 2.06, the count rate at T+24 hours will be 6.9 x 10^-5 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of
3.4 x 10^-15 (3.9 x 10^-15) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00412220.

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


GRB_name: GRB100213B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10417
SUBJECT: GRB 100213B: Swift-BAT refined analysis
DATE:    10/02/14 05:56:33 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), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU),
L. Vetere (PSU) (i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 100213B (trigger #412220)
(Vetere, et al., GCN Circ. 10412).  The BAT ground-calculated position is
RA, Dec = 124.320, 43.464 deg which is 
   RA(J2000)  =  08h 17m 16.8s 
   Dec(J2000) = +43d 27' 51.7" 
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 56%.
 
The mask-weighted light curve shows a FRED-like pulse starting at ~T-5 sec,
peaking at ~T+5 sec, and ending at ~T+150 sec.  Because the burst goes out
of the BAT FOV at T+250 sec (due to an observing constraint), we can not tell
if there if any detectable activity past T+250 sec.  T90 (15-350 keV) is
48.0 +- 16.0 sec (estimated error including systematics).
 
The time-averaged spectrum from T-12.7 to T+35.3 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.13 +- 0.61, 
and Epeak of 39.1 +- 8.8 keV (chi squared 58.8 for 56 d.o.f.).  The 1-sec
peak flux measured from T+10.76 sec in the 15-150 keV band is
0.5 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.04 +- 0.13 (chi squared 67.0 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/412220/BA/


GRB_name: GRB100213A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10418
SUBJECT: GRB 100213A: Enhanced Swift-XRT position
DATE:    10/02/14 08:36:03 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 273 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 100213A, 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 = 349.39183, +43.37892 which is equivalent
to:

RA (J2000): 23h 17m 34.04s
Dec (J2000): +43d 22' 44.1"

with an uncertainty of 2.2 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, MNRAS, 397, 1177).

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


GRB_name: GRB100213B
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10419
SUBJECT: GRB 100213B: PAIRITEL NIR Upper Limits
DATE:    10/02/14 08:57:49 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

A. N. Morgan, B. E. Cobb, C. R. Klein, J. S. Bloom (UC Berkeley), report:

We observed the field of GRB 100213B (Vetere et al., GCN 10412) with
the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began
under good weather conditions at 2010-02-14 02:53:48 UT, ~3.92 hours
after the Swift trigger.  In mosaics (effective exposure time of ~2387
seconds) taken simultaneously in the J, H, and Ks filters, we do not
detect any sources within the XRT error circle, nor at the potential
NOT position (Malesani et al., GCN 10413).

The preliminary photometry yields:

post_burst
t_mid(h)    exp(s)  filt    U. Limit (3 sig)
4.44        2387    J       > 19.2
4.44        2387    H       > 18.2
4.44        2387    Ks      > 17.1

Observations are ongoing.  All magnitudes given in the Vega system,
calibrated to 2MASS.  No correction for Galactic extinction has been
made to the above reported values.


GRB_name: GRB100213A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10420
SUBJECT: GRB 100213A: Swift/UVOT Upper Limits
DATE:    10/02/14 12:39:40 GMT
FROM:    Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>

P.A. Curran (MSSL-UCL) and D. Grupe (PSU) report on behalf of the
Swift/UVOT team:


The Swift/UVOT began settled observations of the field of GRB 100213A
77s after the BAT trigger (Grupe et al., GCN 10411). No optical
afterglow consistent with the XRT position (Beardmore et al., GCN 10418) 
is detected in the initial UVOT exposures.

Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first exposures are:

Filter    T_start(s)   T_stop(s)  Exp(s)  Mag
------------------------------------------------
white     77           227        147     >20.20
v         59           68         9       >17.19
u         289          366        75      >19.7


The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.31 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB100213B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10421
SUBJECT: GRB 100213B: Swift/UVOT Upper Limits
DATE:    10/02/14 12:39:59 GMT
FROM:    Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>

P.A. Curran (MSSL-UCL) and L. Vetere (PSU) report on behalf of the
Swift/UVOT team:


The Swift/UVOT began settled observations of the field of GRB 100213B
158 s after the BAT trigger (Vetere et al., GCN 10412). No optical
afterglow consistent with the XRT position (Vetere et al., GCN 10416) or 
the NOT R-band position (Malesani et al., GCN 10413) is detected in the 
initial UVOT exposures.

Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are:

Filter     T_start(s)   T_stop(s)   Exp(s)   Mag
--------------------------------------------------
white      158          4654        273      >21.17
v          3430         5065        393      >19.64
b          4250         5722        233      >20.38
u          4044         5679        393      >20.38
w1         3840         5475        393      >20.31
m2         3634         5269        393      >21.10
w2         4660         4860        197      >20.00

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB100213B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10422
SUBJECT: GRB 100213B: Gemini-N Observations
DATE:    10/02/14 13:52:00 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara (PSU), R. Chornock (Harvard),D. B. Fox (PSU),
E. Berger (Harvard), report on behalf of a larger collaboration:

"We observed the field of GRB 100213B (Vetere et al., GCN 10412)
with GMOS on the Gemini-North 8-m telescope starting on 2010
Feb 14.24 (~7 hours after the burst).

Inside the refined XRT error circle (GCN #10416) we detect
no new sources in a 2 min r-band acquisition image.
Outside the XRT error circle we clearly detect the source
reported by Malesani et al. (GCN #10413).

We then obtain 2x1200s spectra on this source at central
wavelength 8000A. We detect [OII]3727, H-beta and [OIII]5007
at the common redshift of z =0.604.
At this point is not clear whether this object is related to
GRB 100213B.


We thank the Gemini staff for performing this observation, in
particular Tom Geballe."


GRB_name: GRB100213B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10423
SUBJECT: GRB 100213B: Enhanced Swift-XRT position
DATE:    10/02/14 17:42:01 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.

Using 819 s of XRT Photon Counting mode data and 1 UVOT
image for GRB 100213B, 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 = 124.28226, +43.44773 which is equivalent
to:

RA (J2000): 08h 17m 7.74s
Dec (J2000): +43d 26' 51.8"

with an uncertainty of 3.5 arcsec (radius, 90% confidence). This position
is 3.7" from the object reported by Malesani et al. (GCN Circ. 10413) and
Cucchiara et al (GCN Circ. 10422).

Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and
Evans et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB100213A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10424
SUBJECT: GRB 100213A: Swift-BAT refined analysis
DATE:    10/02/15 14:25:12 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),
N. Gehrels (GSFC), D. Grupe (PSU), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from telemetry downlinks,
we report further analysis of BAT GRB 100213A (trigger #412217)
(Grupe, et al., GCN Circ. 10411).  The BAT ground-calculated position is
RA, Dec = 349.379, 43.370 deg which is 
   RA(J2000)  =  23h 17m 31.0s 
   Dec(J2000) = +43d 22' 13.1" 
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 59%.
 
The mask-weighted light curve shows four spikes between ~T-0.7 and ~T+2.5 sec
plus a low level tail out to ~T+40 sec.  T90 (15-350 keV) is 2.4 +- 0.4 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-0.7 to T+2.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.34 +- 0.15.  The fluence in the 15-150 keV band is 2.7 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+1.01 sec in the 15-150 keV band
is 2.1 +- 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/412217/BA/


GRB_name: GRB100213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10425
SUBJECT: GRB 100213A: GRT Optical Observation
DATE:    10/02/15 20:29:56 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),
T. Okajima (JHU/GSFC), Y. Urata (NCU), C.A. Wallace (FGCU)

We observed the field of GRB 100213A detected by Swift
(trigger #412217; Grupe et al., GCN Circ. 10411) with the 14-inch
Goddard Robotic Telescope (GRT) located at the Goddard Geophysical
and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/).

Total 49 images of 60 sec exposures were taken in the R filter 
starting from February 13 23:42:02 (UT) about 1.2 hours after 
the trigger and stopped on February 14 01:28:00 (UT).  We do 
not detect the optical afterglow both in the individual images 
and the combined image inside the XRT position 
(Beardmore et al., GCN #10418).  The estimated three sigma upper 
limit of the combined image (total exposure of 1800 sec; excluding 
bad quality images) is ~17.5 mag using the USNO-B1 catalog. 


GRB_name: GRB100213B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10426
SUBJECT: GRB 100213B: GRT Optical Observation
DATE:    10/02/15 20:34:15 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),
T. Okajima (JHU/GSFC), Y. Urata (NCU), C.A. Wallace (FGCU)

We observed the field of GRB 100213B detected by Swift
(trigger #412220; Vetere et al., GCN Circ. 10412) with the 14-inch
Goddard Robotic Telescope (GRT) located at the Goddard Geophysical
and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/).

Total 59 images of 60 sec exposures were taken in the R filter 
starting from February 13 23:55:15 (UT) about 0.94 hours after 
the trigger and stopped on February 14 01:50:46 (UT).  We do 
not detect the optical afterglow both in the individual images 
and the combined image inside the XRT position (Evans, GCN #10423).  
The estimated three sigma upper limit of the combined image 
(total exposure of 3540 sec) is ~18.7 mag using the USNO-B1 catalog. 


GRB_name: GRB100213A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10427
SUBJECT: GRB 100213A: Swift-BAT lag analysis indicates probably SHB
DATE:    10/02/16 19:05:36 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. P. Norris (U. Denver), S. D. Barthelmy (GSFC), 
N. Gehrels (GSFC), and D. Grupe (PSU) report:
 
Temporal analysis of BAT data for GRB 100213A suggests
that the burst is likely a member of the short, hard class:

Structures in the burst's most intense pulse complex
are as short as ~ 10-25 ms, typical of most short bursts.

Spectral lag analysis of this most intense pulse complex
indicate a lag between BAT channels 4 (100-350 keV) and
2 (25-50 keV) of ~ 5 ms +- 15 ms.  For the whole event,
the lag between these same channels is ~ 15 ms +- 15 ms.

A Bayesian Block analysis reveals no significant emission
after the T90 duration of 2.4 s (reported in GCN circ. 10424,
Barthelmy et al.) for ~ 400 s following the BAT trigger time.
This is inconsistent only at the 2-sigma level with the finding
in Circ 10424 that there was "low level emission out to T+40 sec",
and we further note that this emission is only in the 15-25 keV band.


GRB_name: GRB100216A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10428
SUBJECT: GRB 100216A Short, hard GRB detected in ground analysis of Swift-BAT data
DATE:    10/02/19 00:32:34 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (NASA/GSFC/CRESST), S. D. Barthelmy (GSFC), D. B. Fox (PSU),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), and D. M. Palmer (LANL)
report on behalf of the Swift team:

At 10:07:00 UT, Swift-BAT detected GRB 100216A as a rate peak (trigger#
412522), but no source was found onboard.  A source was detected in
ground analysis at RA, Dec 154.263, +35.524, which is

RA (J2000)      10h 17m 03.2s
Dec (J2000)     +35d 31' 27.5"

with an estimated 90% containment of 3 arcmin.  The source was detected
at a significance of 6.8 sigma in the ground analysis.  This level
ordinarily indicates a real source, but may have been reached by chance
a few times in the past in similar BAT images.  The maskweighted and raw
lightcurves, however, do appear to be consistent with this location being
the source of the burst.  This position was 41% coded in BAT.  This burst
was also detected by Fermi GBM (trigger 288007622) at a best ground-
analysis position of RA, Dec: 166.9, 56.6 with an estimated uncertainty
of 6.6 degrees (Gruber, private communication).  The entire GBM error
circle was in a highly-coded region of the BAT FOV, and no credible peak
was found any closer to the GBM position.

The burst as seen by BAT consisted of a single peak lasting 0.3 seconds.
The power-law index of the spectrum was 0.6 +/- 0.3.  The fluence in the
interval 15-350 keV was (4.7 +- 3) x 10^-8 erg/cm2.

There was no automated followup because the source was not detected
onboard.  The detailed data on the burst was not available until two days
after the burst.  We note that there is a bright (g'=17.2 mag),
DSS-resolved galaxy, KUG  1014+357 (aka LEDA 86918, aka
SDSS J101700.25+353118.9) at redshift z = 0.038, within the BAT
localization region.  Given the possibility of a low-redshift origin for
this event, and although detectable X-ray emission from short bursts
rarely lasts so long, a limited Swift TOO campaign has been requested
and approved.


GRB_name: GRB100216A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10429
SUBJECT: GRB 100216A: Keck imaging
DATE:    10/02/19 11:57:11 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley (UC Berkeley), J. Meyers, E. Hsiao, N. Suzuki, P. Nugent, 
S. Perlmutter (LBNL), S. B. Cenko, and J. S. Bloom (UCB) report:

We acquired imaging of the field of short-hard burst GRB 100216A 
(Cummings et al., GCN 10428) on 2010-02-19 starting at 07:31 UT, using 
LRIS on Keck 1.  A total of 660 seconds of imaging was acquired in 
R-band and 900 seconds in g-band simultaneously.  The imaging covers 
approximately 90% of the BAT error circle including the nearby galaxy 
mentioned in GCN 10428, a barred spiral at z=0.0378.  In a preliminary 
reduction of the R-band frames we identify no new source within the 
field, down to the SDSS limit of approximately R>22 mag.


GRB_name: GRB100219A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10430
SUBJECT: GRB 100219A: Swift detection of a burst
DATE:    10/02/19 15:32:18 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

A. Rowlinson (U Leicester), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), V. D'Elia (ASDC), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), O. Godet (U Leicester),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL),
O. M. Littlejohns (U Leicester), V. Mangano (INAF-IASFPA),
J. Mao (INAF-OAB), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), C. Pagani (U. Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC),
B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU), M. C. Stroh (PSU)
and L. Vetere (PSU) report on behalf of the Swift Team:

At 15:15:46 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100219A (trigger=412982).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 154.221, -12.559 which is 
   RA(J2000)  =  10h 16m 53s
   Dec(J2000) = -12d 33' 31"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). As is usual for an image trigger, the BAT light
curve shows nothing of interest. 

The XRT began observing the field at 15:18:45.0 UT, 178.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 154.2024,
-12.5671 which is equivalent to:
   RA(J2000)  = 10h 16m 48.58s
   Dec(J2000) = -12d 34' 01.7"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 71 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
6.51e+20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 183 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
0.08. 

Burst Advocate for this burst is A. Rowlinson (bar7 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: GRB100218A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10431
SUBJECT: GRB 100218A : Fermi GBM detection
DATE:    10/02/19 16:48:55 GMT
FROM:    David Tierney at UCD  <david.tierney@ucd.ie>

Dave Tierney (UCD) 
reports on behalf of the Fermi GBM Team: 

"At 04:38:45.93 UT on 18 February 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100218A (trigger 288160727 / 100218194).

The on-ground calculated location, using the GBM trigger 
data, is RA = 206.6, DEC = -11.9 (J2000 degrees, 
equivalent to 13 h 46 m, -11 d 54 '), with an uncertainty 
of 2.2 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 37 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 30.8 +/- 1.6 s (8-1000 keV). 
The time-averaged spectrum from T0-4.1 s to T0+28.67 s 
is best fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.50 (+0.28/-0.25) and
the cutoff energy, parameterized as Epeak, is 184.20 (+52.40/-29.70) keV
(cstat 845 for 485 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(2.58 +/- 0.21)E-6 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+4.7 s in the 8-1000 keV band 
is 1.4 +/- 0.2 ph/s/cm^2.

A Band function fits the spectrum equally well (cstat 840 for 484 d.o.f.) 
with Epeak= 131.60 (+32.70/-21.70) keV, alpha = -0.14 (+0.41/-0.33) 
and beta = -2.00 (+0.18/-0.30). 


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


GRB_name: GRB100219A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10432
SUBJECT: GRB 100219A: Swift/UVOT Detection of a Source near the XRT Position 
DATE:    10/02/19 17:29:24 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA),
N. P. M. Kuin (UCL-MSSL), and
A. Rowlinson (U Leicester)
report on the behalf of the Swift/UVOT team:

       The Swift/UVOT observed the field of GRB 100219A (Rowlinson et
al. 2010, GCN Circ. 10430) starting 183 s after the BAT detection.  We
do not detect any source inside the XRT error circle, but we do detect
a source 3.8 arcsec north of the centre of the 2.1 arcsec XRT error
circle.  This source is not present in the SDSS DR7, USNO B1.0, or
2MASS point source catalogues.  It is at the detection limit of the
DSS, so it is unclear if this is a new source.  The preliminary UVOT
position is

     RA (J2000)  10:16:48.54  =  154.20225 (deg)
    Dec (J2000) -12:33:57.9   =  -12.56608 (deg)

with an estimated uncertainty of 1.0 arcsec (radius, 90% confidence,
statistical + systematic).

Preliminary magnitudes for this source are

Filter   TSTART    TSTOP   Exposure      Mag   Err   Sigma
---------------------------------------------------------------
white       183      333        150    20.70  0.34     3.2
white       875     1025        150   >20.9            3-sigma UL
u           341      591        250    21.00  0.56     2.0
---------------------------------------------------------------

It is not clear if this source is fading, or if it is associated with
GRB 100219A.

     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} = 0.08 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: GRB100219A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10433
SUBJECT: GRB 100219A: Pre-explosion imaging and host candidate 
DATE:    10/02/19 17:55:52 GMT
FROM:    Josh Bloom at UC Berkeley  <jbloom@astron.berkeley.edu>

J. S. Bloom (UC Berkeley) and P.  E. Nugent (LBNL) report:

"We co-added 27 archival images from the DeepSky* project at Palomar Observatory covering the field of GRB 100219A (Rowlinson et al. 2010, GCN Circ. 10430). The images were obtained between 2004-2007 from the Palomar-Quest Consortium at the Oschin Schmidt telescope.  The limiting magnitude of the stack is approximately R ~ 22.5 mag.

In the combined image we detect a faint (R = 21.0 +/- 0.3 mag relative to nearby USNO catalog stars) slightly extended source, outside the current XRT error circle to the North by ~3.7".  The approximate (+/- 1") coordinates of the source are:

RA = 10:16:48.52, DEC = -12:33:57.5  (J2000)

Within the errors, this is coincident with the UVOT source reported by Holland et al. (GCN 10432). This is a potential (lowish redshift) host candidate of the event and we encourage spectroscopic follow-up."

* http://supernova.lbl.gov/~nugent/deepsky.html


GRB_name: GRB100219A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10434
SUBJECT: GRB 100219A: Swift-BAT refined analysis
DATE:    10/02/19 21:13:35 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),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), A. Rowlinson (U Leicester), T. Sakamoto (GSFC/UMBC),
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 100219A (trigger #412982)
(Rowlinson, et al., GCN Circ. 10430).  The BAT ground-calculated position is
RA, Dec = 154.202, -12.555 deg which is 
   RA(J2000)  =  10h 16m 48.4s 
   Dec(J2000) = -12d 33' 19.4" 
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 71%.
 
The mask-weighted light curve shows a roughly triangular shaped peak
starting at ~T-10sec, peaking at ~T+30 sec, and ending at ~T+50 sec
(possibly out to ~T+100 sec).  T90 (15-350 keV) is 18.8 +- 5.0 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+19 to T+45 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.34 +- 0.25.  The fluence in the 15-150 keV band is 3.7 +- 0.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+31.89 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/412982/BA/


GRB_name: GRB100216A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10435
SUBJECT: GRB 100216A: XRT Refined Analysis
DATE:    10/02/19 23:51:55 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

A. Rowlinson (U. Leicester), K. Page (U. Leicester) and N. Lyons (U.
Leicester) report on behalf of the Swift-XRT team:

We have analysed 9.9 ks of XRT data for GRB 100216A (Cummings et al. GCN
Circ. 10428), from 214.4 ks to 249.2 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode.

We do not detect any fading source within the BAT refined error circle
of Cummings et al. (GCN Circ. 10428). A source is detected within the
BAT refined error circle at RA, Dec = 154.25836, +35.56772 which is
equivalent to:

RA (J2000): 10h 17m 2.0s
Dec (J2000): +35d 34' 3.8''

with an uncertainty of 5 arcsec (radius, 90% confidence) and is likely
to be the known X-ray source 1RXS J101702.9+353404. This source has a
count rate of 0.004 count s^-1, corresponding to a flux of 2.6e-13 erg
cm^-2 s^-1, however fading cannot be determined at this time and futher
observations are being planned.

The three sigma upper limit 0.3 - 10 keV count rate for a source at any
other position within the BAT error circle is 6e-4 count s^-1, which
corresponds to an observed flux limit of 2.3e-14 erg cm^-2 s^-1
(assuming a typical count-to-observed flux conversion factor of 3.8e-11
erg cm^-2 ct^-1, Evans et al., 2009, MNRAS, 397, 1177).

The results of the XRT-team automatic analysis are available at
http://www.swift.acc.uk/xrt_products/00020127.
This circular is an official product of the Swift-XRT team.


GRB_name: GRB100219A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10436
SUBJECT: GRB 100219A: Swift/UVOT Detection of the Optical Afterglow 
DATE:    10/02/20 00:18:39 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA) and
A. Rowlinson (U. Leicester) report
on the behalf of the Swift UVOT team:

        Swift/UVOT began settled observations of the field of GRB
100219A starting 161 s after the BAT trigger (Rowlinson, et al. 2010,
GCN Circ. 10430).  Settled exposures started at T+183 s.  The source
reported by Holland, et al. (2010, GCN Circ. 104322) is seen in the
white and u-band exposures.  Preliminary 3-sigma magnitudes and upper
limits are

Filter   T_start   T_stop   Exp(s)      Mag  Err
------------------------------------------------------
white       183       333     150     20.91 0.28
white       875      1718     225    >21.6  3-sigma UL
v           673      1767     136    >19.7  3-sigma UL
b           598      1693     117    >20.5  3-sigma UL
u           341      1668     343     20.35 0.35
uvw1        722      1812     113    >19.9  3-sigma UL
uvm2        697      1792      39    >18.3  3-sigma UL
uvw2        648      1297      78    >19.5  3-sigma UL
------------------------------------------------------

     The fading observed between T+183 s and T+875 s suggests that
this is the afterglow of GRB 100219A superimposed on the host galaxy
candidate of Bloom and Nugent (2010, GCN Circ. 10433).  The weak
detection in the u band suggests that this source has a redshift of
less than approximately 2.8.

     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} = 0.08 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).


GRB_name: GRB100219A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10437
SUBJECT: GRB 100219A: Enhanced Swift-XRT position
DATE:    10/02/20 00:49:00 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 1938 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 100219A, 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 = 154.20206, -12.56671 which is equivalent
to:

RA (J2000): 10h 16m 48.49s
Dec (J2000): -12d 34' 00.2"

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, MNRAS, 397, 1177).

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


GRB_name: GRB100219A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10438
SUBJECT: GRB 100219A: NOT OA observations
DATE:    10/02/20 02:40:12 GMT
FROM:    Pall Jakobsson at U of Iceland  <pja@raunvis.hi.is>

P. Jakobsson (U. Iceland), D. Malesani (DARK, NBI),
C. Villforth (Tuorla Observatory), J. Hjorth,
D. J. Watson (DARK, NBI) and N. R. Tanvir (U. Leicester)
report on behalf of a larger collaboration:

Using StanCam on the Nordic Optical Telescope (NOT) we have
obtained R-band imaging of the GRB 100219A field
(Rowlinson et al., GCN 10430) on Feb 20.02 (9.25 hours after
the burst). Right in the middle of the revised XRT error circle
(Evans et al., GCN 10437) we detect an object at the following
coordinates:

RA(J2000) = 10:16:48.49
Dec(J2000) = -12:34:00.5

Its magnitude is R = 22.2 +- 0.1 based on USNO-B1 calibration. The
object first noticed by Holland & Rowlinson (GCN 10436) and found in
pre-explosion images by Bloom & Nugent (GCN 10437) is well detected in
our images, and is located 3.1" NNE of the above object.

An image of the field is shown at:

http://www.astro.ku.dk/~malesani/GRB/100219A/finder_100219A.png


GRB_name: GRB100219A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10439
SUBJECT: GRB 100219A: GROND observations
DATE:    10/02/20 02:53:11 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

T. Kruehler (MPE), A. Nicuesa (Tautenburg Obs.), S. Klose (Tautenburg
Obs.), J. Greiner and P. Afonso (both MPE Garching) report on behalf of
the GROND team:

We observed the field of GRB 100219A (Swift trigger #412982; Rowlinson et
al., GCN #10430) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at LaSilla
Observatory (Chile).

Observations started on 20 February 2010 at 00:30 UT, 8.7 hours after the
GRB trigger.

Inside the XRT error circle (Evans et al., GCN #10437), we detect the
source mentioned in Jakobsson et al. GCN #10438, spatially separated by 3"
from the object mentioned in Holland et al. GCN#10432 and Bloom & Nugent
GCN #10433.

The object inside the XRT error circle is well detected in the r' band and
redder, but not in g'. Preliminary photometry yields an AB magnitude of
i'=21.5 calibrated against the GROND zeropoint at 9.0 hours after the
trigger. At the moment no statement about variability can be made.
However, if this is the afterglow of GRB 100219A, its colors indicate a
relatively high redshift event (z around 4.5).


GRB_name: GRB100219A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10440
SUBJECT: GRB100219A Akeno and Okayama MITSuME Optical Observation
DATE:    10/02/20 03:43:34 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>

D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), H. Nakajima,
Y.Yatsu, Y.A.Mori, A.Endo, T. Shimokawabe, and N. Kawai(Tokyo Tech),
S. Nagayama (NAOJ), M. Yoshida (Hiroshima) and K. Ohta (Kyoto)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 100219A (Rowlinson et al. GCN 10430)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Akeno Observatory and Okayama
Astrophysical Observatory. We found the afterglow at the XRT
position (Holland et al. GCN 10432, Rowlinson et al. GCN 10435
and Evans et al. GCN 10437) in Rc and Ic band.

The coordinates of the object are:
RA(J2000)   10:16:48.50 (+- 0.5 arcsec)
DEC(J2000) -12:34:00.6  (+- 0.3 arcsec)

But we could not detect the optical afterglow previously
reported by Holland and Rowlinson (GCN 10436)

Photometric results and three sigma upper limits of the OT are
listed below. We used GSC2.3 catalog for flux calibration.

Akeno Observatory:
The observation started on 2010-02-19 15:17:30 UT (104s after the
trigger).
PDAY     MID-UT    T-EXP    g'      Rc       Ic
-----------------------------------------------------
0.00471  15:22:34   540.0        19.8+-0.3 18.5+-0.3
----------------------------------------------------

Okayama Astrophysical Observatory:
The observation started on 2010-02-19 15:20:08 UT (262 sec after
the trigger).
PDAY     MID-UT    T-EXP    g'      Rc       Ic
-----------------------------------------------------
0.00675  15:25:30   540.0 >19.1   >19.0    17.8+-0.2
0.01428  15:36:21   540.0 >19.1   >19.1    17.5+-0.1
0.02177  15:47:07   540.0 >19.1  18.4+-0.2 18.1+-0.3
0.06589  16:50:40  3000.0 >19.4   >19.7    18.9+-0.3
-----------------------------------------------------


GRB_name: GRB100219A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10441
SUBJECT: GRB 100219A: VLT/X-shooter redshift
DATE:    10/02/20 04:48:54 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

P. Groot (Radboud Univ. Nijmegen), L. Kaper, L. Ellerbroek (Univ. 
Amsterdam), D. Malesani (DARK/NBI), P. Jakobsson (Univ. Iceland), J. P. 
U. Fynbo, J. Hjorth, D. J. Watson (DARK/NBI), and E. Mason (ESO), report 
on behalf of a larger collaboration:

We observed the optical objects associated to GRB 100219A (Rowlinson et 
al., GCN 10430; Holland & Rowlinson, GCN 10432; Bloom & Nugent, GCN 
10433; Jakobsson et al., GCN 10438; Kruehler et al., GCN 10439) with the 
VLT equipped with the X-shooter spectrograph. The slit was oriented so 
to include both the pre-existing object and the candidate afterglow. 
Observations started on 2010 Feb 20.105 UT (0.47 days after the GRB), 
for a total exposure time of 4x1200 s.

In a preliminary analysis of the spectra, we detect a clear signal from 
both objects. The continuum from the candidate afterglow is only 
detected redward of ~5310 AA. A further spectral break is recognised at 
~7060 AA. This is consistent with the onset of the Lyman limits and of 
the Lyman alpha forest at a common redshift z = 4.8. Our observations 
are consistent with the photometric redshift indicated by the GROND 
observations (Kruehler et al., GCN 10439).

The high luminosity of the object and its spectral shape indicate that 
this is indeed the afterglow of GRB 100219A.

The spectrum of the nearby galaxy implies a significantly lower 
redshift, around z=0.25, hence it is unrelated to the GRB.

We caution that the above analysis (particularly the wavelength 
solution) is preliminary. Reduction with updated calibrations is 
underway. We would like to thank Alain Smette (ESO) for his kind assistance.


GRB_name: GRB100216A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10442
SUBJECT: GRB 100216A: Swift/UVOT Observations
DATE:    10/02/20 05:01:15 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and A. Rowlinson (U. Leicester) report on behalf of
the SWIFT-UVOT team:

We have analysed 9787 ks of UVOT data for GRB 100216A (Cummings et al.,
GCN Circ. 10428), from 214.4 ks to 249.2 ks after the BAT trigger. The
data are entirely in the UVW2 filter.

We identify a source within the error circle of the XRT position given
by Rowlinson et al. (GCN Circ. 10435) with a UVW2 magnitude of 17.59
+- .03 and a position of 154.25872, +35.56806, which is equivalent to:

    RA(J2000)  = 10h 17m 02.09s
    Dec(J2000) = +35d 34m 05.0"

with a 90% confidence interval of 0.6 arc sec.  However, this source is
also seen in the Digital Sky Survey and exhibits no fading or measurable
variability over the 35 ks of observations.  It is likely the
ultraviolet counterpart to the known X-ray source 1RXS
J01702.9+353404 identified by Rowlinson et al.  We show no other
bright source near the XRT position to a 3-sigma upper limit of
UVW2=22.2.

    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} = 0.10 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).


GRB_name: GRB100219A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10443
SUBJECT: GRB 100219A - Gemini South Spectroscopy
DATE:    10/02/20 06:58:52 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

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

We have obtained spectra of the proposed host galaxy (Bloom and
Nugent, GCN 10433; Holland et al., GCN 10436) and the optical afterglow
(Jakobsson et al., GCN 10438; Kruehler et al., GCN 10439) of
GRB100219A (Rowlinson et al., GCN 10430) with the Gemini Multi-Object
Spectrograph mounted on the 8-m Gemini South telescope.  Our first
sequence of 2 x 900 s observations started at 2:44 UT on 20 February
2010 and cover the range from 6500 - 9500 A.  Only the proposed host
galaxy was contained on the slit for these spectra.  Our second set,
starting immediately afterward, cover the wavelength range from 4500 -
7500 A and both the proposed host and afterglow are positioned on the
slit.

From the nearby galaxy, we detect strong emissions features corresponding
to H-alpha, H-beta, and [O III] at a common redshift of z = 0.217.

The spectrum of the afterglow shows a strong break at ~ 6880 A, with
only faint continuum blueward of this feature.  Interpreting this as
the Lyman-alpha break, this correponds to a redshift of z ~ 4.7.  We
find marginal evidence for narrow absorption features corresponding to Si
II and Si II* at z = 4.65 redward of the break - however the relatively
low signal-to-noise ratio of our spectrum in this regime makes this result
somewhat uncertain.

Our derived redshifts for both objects are similar to, though slightly
less than, the values derived by Groot et al. (GCN 10441) from the
VLT/X-shooter.  They are also consistent with the photometric redshift of
z ~ 4.5 derived by Kruehler et al. (GCN 10439) from GROND.


GRB_name: GRB100219A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10444
SUBJECT: GRB 100219A: XRT refined analysis
DATE:    10/02/20 07:11:16 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

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

We have analysed 3.8 ks of XRT data for GRB 100219A (Rowlinson et al.
GCN Circ. 10430), from 207 s to 28.4 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Evans et al. (GCN. Circ 10437).

The light curve can be modelled with an initial power-law decay with an
index of alpha=1.53 (+0.28, -0.22), followed by a break at T+785 s to an
alpha of 0.57 (+/-0.06).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.72 (+0.16, -0.13). The
best-fitting absorption column is 8.8 (+4.2, -0.0) x 10^20 cm^-2, in
excess of the Galactic value of 6.5 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 4.5 x 10^-11 (5.3 x 10^-11) erg
cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
0.57, the count rate at T+24 hours will be 0.035 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.6 x
10^-12 (1.8 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/00412982.
This circular is an official product of the Swift-XRT team.


GRB_name: GRB100219A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10445
SUBJECT: GRB 100219A: X-shooter refined analysis
DATE:    10/02/20 21:32:41 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo, C.C. Thoene (INAF/OAB), S.D. Vergani
(APC/Univ. Paris 7), B. Milvang-Jensen, J. Fynbo (DARK/NBI)
report on behalf of the X-shooter GRB collaboration:

We continued with the analysis of X-shooter's spectrum
(Groot et al. GCN 10441) obtained for the afterglow of
GRB 100219A (Rowlinson et al. GCN 10430). Additionally to
the strong Ly-alpha absorption reported in the previous GCN
and the SiII and SiII* absorptions suggested by Cenko et al.
(GCN 10443) we detect several other absorption features,
including SII, OI, OI*, CII, CII*, SiIV, CIV, FeII, AlII and
AlIII at a redshift of 4.6667 +/- 0.0005. We also detect an
intervening system at z = 2.1810 +/- 0.0005 through the
identification of FeII, MgII and MgI. A second intervening
system might be present at z = 1.7980 +/- 0.0005 identified
by faint MgII and MgI absorptions. Further analysis is ongoing.


GRB_name: GRB100213B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10446
SUBJECT: GRB
DATE:    10/02/22 18:00:16 GMT
FROM:    Janos Kelemen at Konkoly Obs/Hungary  <kelemen@konkoly.hu>

GRB 100213B R band observations

J. Kelemen (kelemen at konkoly.hu) on behalf of the GRB OT observing program
at the Konkoly Observatory.


On 15 february 2010 19:56:20 UT we observed the field of GRB 100213B detected
by Swift (trigger #412220; Vetere et al., GCN 10412) with a 60/90 cm  Schmidt
telescope located at the Mountain Station of the Konkoly Observatory using R
filter. The total exposure of the coadded images were 2700 s. We examined both
the XRT position and the position reported D. Malesani et al. GCN 10413. 
No new object brighter than 21.3 +/- 0.2 was found. 

Time     Mag     Error.      Flag.
[s]     [R]    [1-sigma]  
-------------------------------------
161866   21.30   0.2      Upper Limit
------------------------------------- 

This message can be cited. 


GRB_name: GRB100223A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10448
SUBJECT: GRB 100223A: Fermi GBM detection
DATE:    10/02/24 03:27:41 GMT
FROM:    Sylvain Guiriec at UAH  <sylvain.guiriec@lpta.in2p3.fr>

Colleen Wilson-Hodge (NASA) and Sylvain Guiriec (UAH)
report on behalf of the Fermi GBM Team:

"At 02:38:09.31 UT on 23 February 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100223A (trigger 288585491 / 100223110).

The on-ground calculated location, using the GBM trigger
data, is RA = 104.1, DEC = +2.8 (J2000 degrees,
equivalent to 6 h 56 m, 2 d 48 '), with an uncertainty
of 3.6 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 76 degrees.

GBM triggered on a soft peak lasting about 0.05 s followed few ms later by
a longer and harder one. The T90 duration is about 0.206 s (50-300 keV).
The time-averaged spectrum from T0-0.01 s to T0+0.22 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.31 +/- 0.08 and
the cutoff energy, parameterized as Epeak, is 1143 +/- 109 keV
(Castor C-stat 570.83 for 605 d.o.f.).

The event fluence (10-1000 keV) in this time interval is
(1.42 +/- 0.04)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.01 s in the 10-1000 keV band
is 12.5 +/- 0.4 ph/s/cm^2.

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


GRB_name: GRB100225A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10449
SUBJECT: GRB 100225A: Fermi GBM detection
DATE:    10/02/25 15:41:30 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

S. Foley (MPE) and S. McBreen (UCD/MPE) report on
behalf of the Fermi GBM Team:

"At 02:45:31.15 UT on 25 February 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100225A (trigger 288758733 / 100225115).

The on-ground calculated location, using the GBM trigger
data, is RA = 312.5, DEC = -54.9 (J2000 degrees,
equivalent to 20 h 50 m, -54 d 54 '), with an uncertainty
of 2.4 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 consists of two main pulses
with a duration (T90) of about 13 (+/-3) s (50-300 keV)
starting at -0.256 s. The time-averaged spectrum
from T0-3.8 s to T0+13.6 s is well fit by
a power law function with an exponential high energy cutoff.
The power law index is -0.80 (+0.09/-0.08) and
the cutoff energy, parameterized as Epeak, is
527.30 (+105.00/-76.10) keV (CSTAT 438 for 361 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(7.6 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+6.4 s in the 8-1000 keV band
is 4.13 +/- 0.20 ph/s/cm^2.

A Band function fits the spectrum equally well (CSTAT 436 for 360 d.o.f.)
with Epeak= 428.00 (+130.00/-86.00) keV, alpha = -0.72 (+0.13/-0.12)
and beta = -2.15 (+0.21/-0.75).


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


GRB_name: GRB100225A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10450
SUBJECT: GRB 100225A: Fermi LAT detection
DATE:    10/02/25 17:24:50 GMT
FROM:    Julie McEnery at NASA/GSFC  <julie.e.mcenery@nasa.gov>

Fred Piron (LPTA), Masanori Ohno (ISAS/JAXA), Francesco
de Palma (INFN Bari), Elena Moretti (INFN Trieste) and Julie
McEnery (GSFC) report on behalf of the Fermi LAT team

At 02:45:53 (UT) on 25 Feb 2010, the Fermi Large Area
Telescope (LAT) detected gamma rays from the GRB 100225A,
which was triggered and located by the Fermi Gamma-ray Burst
Monitor (GBM) (trigger 288758733 / 100225.115, GCNC 10449).
The angle of  the GBM position position with respect to the LAT
boresight  was ~60 degrees at the time of the LAT detection,
which is just  within the LAT field of view.

The data from the Fermi LAT shows a weak increase in the event
rate that is spatially and temporally correlated with the GBM
emission. It is a relatively weak detection (~4 sigma)
with fewer than 10 excess events.

The best LAT on-ground localization is found to be (RA, Dec =
310.3, -59.4) (J2000) with a 90% containment radius of 1.30 deg
(statistical; 68% containment radius: 0.9 deg) which is consistent
with the GBM localization.

Further analysis is ongoing.

The point of contact for this burst is Fred Piron 
(Frederic.PIRON@lpta.in2p3.fr)

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: GRB100224A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10451
SUBJECT: GRB 100224A SHB found in ground analysis of BAT data
DATE:    10/02/25 20:00:59 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

J. R. Cummings (GSFC/UMBC), H. A. Krimm (GSFC/USRA),
F. E. Marshall (NASA/GSFC), and D. M. Palmer (LANL)
report on behalf of the Swift team:

At 15:20:10 UTC, Swift-BAT rate-triggered on GRB 100224A (trigger#
413805).  No source was found on board.  A source was found in ground
analysis at RA, Dec 83.467, -7.994, which is

RA (J2000) = 05h 33m 52.1s
Dec (J2000) = -07d 59' 37"

with an estimated error of 3 arcmin (90% containment).

The burst had two main peaks, the first larger, at T+0.2 and T+0.5 sec,
the first about 0.1 sec long, the second about 0.3 sec long.

The spectrum is well fit by a simple powerlaw with a photon index of
0.98 +- 0.23.  The fluence (15-150 keV) from T+0.17 to T+0.625 sec
was 3.2 +- 2 x 10^-8 ergs/cm^2/sec (1 sigma error estimates).

Since the source was not detected onboard, there are no automated
products for this burst. Since the burst is old for a SHB, there
are currently no plans for Swift followup observations.


GRB_name: GRB100219A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10452
SUBJECT: GRB 100219A: GAO 150cm telescope Optical Observation
DATE:    10/02/26 01:01:58 GMT
FROM:    Kenzo Kinugasa at Gunma Astro. Obs/Japan  <kinugasa@astron.pref.gunma.jp>

K. Kinugasa, S. Honda, H. Takahashi, H. Taguchi, O. Hashimoto 
 (Gunma Astronomical Observatory) report:

 The position of GRB 100219A (Rowlinson et al., GCN 10430) was observed
with the 150 cm telescope of Gunma Astronomical Observatory. Starting at 
16:06:16 UT on Feb.19 (0.84 hour after the trigger), both Rc and Ic 
frames were acquired for sets of 5 x 3-min exposures.

 Inside the XRT error circle (Evans et al., GCN 10437), we detected the
optical counterpart reported by Jakobsson et al. (GCN 10438), Kruehler 
et al. (GCN 10439), and Kuroda et al. (GCN 10440) in Rc and Ic stacked 
images. We estimated the Rc and Ic magnitudes relative to USNO-B1.0 R2 
and I magnitudes, respectively.

mid-UT     T0+(d)     exp       mag.            
-----------------------------------------------------
16:15:24   0.0414    5x3min     Rc=20.5+-0.2     
16:34:45   0.0549    5x3min     Ic=19.6+-0.3     
-----------------------------------------------------
 


GRB_name: GRB100219A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10453
SUBJECT: GRB 100219A: optical observations
DATE:    10/02/26 02:48:20 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, D. Shakhovskoy (CrAO), A. Pozanenko (IKI)  report on behalf 
of larger GRB  follow-up collaboration:

We observed the field of the Swift GRB 100219A (Rowlinson  et al. GCN 10438) 
with AZT-11 telescope of CrAO starting (UT) Feb. 19  22:54 (7.6 hours after 
burst onset). We detect the galaxy (previously reported by Holland & 
Rowlinson (GCN 10436),  Bloom & Nugent (GCN 10437)). The coordinates of the 
galaxy are (J2000) RA= 10 16 48.61, Dec= -12 33 57.15 (with uncertainties 
0.5 arcsec in both coordinates). We do not detect optical afterglow 
(Jakobsson et al. GCN 10430, Kruehler et al. GCN 10439). The photometry is 
based on USNO-B1.0 star   0774-0276292   (assuming R=16.90):

T0+      Filter,   Exposure,  mag.               Object
(mid, d)              (s)

0.3364   R       20x180       21.3 +/- 0.25    galaxy
0.3364   R       20x180    > 21.8                OT


GRB_name: GRB100213B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10454
SUBJECT: GRB 100213B: Mondy optical observations  
DATE:    10/02/26 02:54:05 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Klunko (ISTP), A. Volnova (SAI MSU), A. Pozanenko (IKI) on behalf of 
larger GRB follow up collaboration  report:

We observed the field of GRB 100213B (Vetere  et al., GCN 10412)   with 
AZT-33IK telescope of Sayan observatory (Mondy) starting Feb. 14 (UT) 
14:54:31.  We do not detect any sources in enhanced XRT error circle (Evans, 
GCN 10423).  The upper limit (3 sigma) of  stacked image is based on 
USNO-B1.0 nearby stars:

T0+      Filter,   Exposure,   mag.
(mid, d)             (s)

0.6801   R       94x30     > 20.80


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10455
SUBJECT: GRB 100206A: optical observations in Terskol
DATE:    10/02/26 02:58:35 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

M.Andreev,  A.Sergeev, N.Parakhin, N.Karpov (Terskol Branch of  Institute of
Astronomy), Yu. Kuznietsova (Main Astronomical Observatory NASU), V.Petkov
(Baksan Neutrino Observatory INR) and A. Pozanenko (IKI) on behalf of larger
GRB follow up collaboration report:

We observed the field of the Swift GRB 100206A (Krimm  et al. GCN  10376)
with the Z-600 telescope of Mt.Terskol observatory in R-filter  on  Feb. 06
starting at (UT) 15:49. We obtained three series under variable weather
conditions and improving seeing.

The upper limits of  point like object in combined images of  each series
are presented below.
The photometry is based on the USNO-B1.0 reference stars 1032-0043920
(assuming  R2=15.76) and 1031-0041081 (R2=15.78):

T0+     Filter, Exposure, mag.
(mid, d)             (s)

0.1034    R  10x120   >20.5
0.1235    R  20x120   >20.8
0.1631    R  20x120   >21.4

The nearby galaxy (Miller et al., GCN 10377, Bhattacharya et al., GCN 10380,
Guziy et al., GCN 10384, Leloudas et al., GCN 10387, Cenko et al., GCN
10389, Morgan et al., GCN 10390, Mao et al. GCN 10392, Nicuesa et al. GCN
10396) is detected in last series in coordinates (J2000) RA=03 08 39.17
Dec=+13 09 28.7  +/-0.5" and  magnitude R=21.3 +/-0.3. No objects is
detected in enhanced XRT error circle (Goad et al. GCN 10378).


GRB_name: GRB100206A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10456
SUBJECT: GRB 100206A: optical observations in CrAO
DATE:    10/02/26 03:00:50 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, D. Shakhovkoy (CrAO), A. Pozanenko (IKI)  report on behalf of
larger GRB  follow-up collaboration:

We observed the field of the Swift GRB 100206A (Krimm  et al. GCN  10376)
with AZT-11 telescope of CrAO between (UT) Feb. 06  16:09 -- 17:10 under
poor seeing of about 6 arcsec. No objects is detected in enhanced XRT error
circle (Goad et al. GCN 10378).

The upper limit of point like object in a stacked image based on USNO-B1.0
star  1031-0041090  (assuming R2=16.63)  is following:

T0+      Filter,   Exposure, mag.
(mid, d)              (s)

0.1315   R       20x180    > 21.7


GRB_name: GRB100224B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10457
SUBJECT: GRB 100224B: Fermi GBM detection
DATE:    10/02/26 15:58:41 GMT
FROM:    Suzzanne Foley at MPE  <sfoley@mpe.mpg.de>

Suzanne Foley (MPE)
reports on behalf of the Fermi GBM Team:

"At 02:40:55.48 UT on 24 February 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100224B (trigger 288672057 / 100224112).

The on-ground calculated location, using the GBM trigger
data, is RA = 269.56, DEC = -17.08 (J2000 degrees,
equivalent to 17 h 58 m, -17 d 05 '), with an uncertainty
of 1.6 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 88 degrees.

The GBM light curve consists of 3 peaks
with a duration (T90) of about 77 (+/-2) s (50-300 keV)
starting at T0-5.6 s. The time-averaged spectrum from
T0-7.2 s to T0+71.7 s is well fit by a power law function
with an exponential high energy cutoff.  The power law
index is -1.36 (+0.07/-0.06) and the cutoff energy,
parameterized as Epeak, is 181.40 (+31.50/-23.60) keV
(CSTAT 591 for 361 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.08 +/- 0.05 )E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+16.4 s in the 8-1000 keV band
is 10.7 +/- 0.3 ph/s/cm^2.


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

[GCN OPS NOTE(26feb10): The administrator corrected the mistaken
first name of the author. Apologies.]


GRB_name: GRB100302A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10458
SUBJECT: GRB 100302A: Swift detection of a burst
DATE:    10/03/02 20:14:02 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (NASA/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU),
O. Godet (U Leicester), D. Grupe (PSU),
S. T. Holland (CRESST/USRA/GSFC), S. Immler (CRESST/GSFC/UMD),
J. A. Kennea (PSU), R. Margutti (Univ Bicocca&OAB),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
M. Perri (ASDC), M. H. Siegel (PSU), M. A. Stark (PSU),
E. Troja (NASA/GSFC/ORAU), T. N. Ukwatta (GSFC/GWU) and
L. Vetere (PSU) report on behalf of the Swift Team:

At 19:53:06 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100302A trigger=414592).  Swift slewed immediately to the 
burst.  The BAT on-board calculated location is 
RA, Dec 195.344, +74.581 which is 
   RA(J2000) = 13h 01m 23s
   Dec(J2000) = +74d 34' 51"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single broad peak 
with a duration of about 35 sec, beginning about 40 sec after the trigger
time (the beginning of the 64-second interval for this "image trigger").  
The peak count rate was ~500 counts/sec (15-350 keV), at ~55 sec after 
the trigger. 

The XRT began observing the field at 19:55:11.9 UT, 125.4 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
195.5146, 74.5895 which is equivalent to:
   RA(J2000)  = 13h 02m 3.50s
   Dec(J2000) = +74d 35' 22.1"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 166 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
1.92e+20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 1.96e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 132 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 J. R. Cummings (jayc 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: GRB100302A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10459
SUBJECT: GRB 100302A: Skynet/DAO Observations
DATE:    10/03/02 22:45:23 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, K. Ivarsen, A. LaCluyze, D. Reichart, R. Egger, A. Foster, J. 
Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. 
Nysewander report:

Skynet observed the Swift/BAT localization of GRB 100302A (Cummings et al., 
GCN 10458) with the 16" telescope at the Dolomiti Astronomical Observatory 
in Italy beginning 2.7 minutes after the trigger (1.3 minutes after 
notification) in Red, which we have calibrated to R.

We do not detect the afterglow (Cummings et al., GCN 10458).  Stacking only 
images that increase the limiting magnitude yields:

mean                                             1-sig.  1-sig.
time                         3-sig.              sys.    stat.
since                        lim.    cal.        cal.    cal.
trig.  tel.  exp.      fil.  mag.    stars       unc.    unc.
(m)          (# x s)                             (mag)   (mag)

73.3   DAO   28 x 160  Red   20.3    78 USNO B1  0.429   0.000


GRB_name: GRB100302A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10460
SUBJECT: GRB 100302A: Enhanced Swift-XRT position
DATE:    10/03/02 23:10:26 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 478 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 100302A, 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 = 195.51524, +74.58959 which is equivalent
to:

RA (J2000): 13h 02m 3.66s
Dec (J2000): +74d 35' 22.5"

with an uncertainty of 1.9 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, MNRAS, 397, 1177).

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


GRB_name: GRB100302A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10462
SUBJECT: GRB 100302A, Swift-BAT refined analysis
DATE:    10/03/03 03:09:06 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@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),
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 100302A (trigger #414592)
(Cummings, et al., GCN Circ. 10458).  The BAT ground-calculated position
is RA, Dec = 195.504, 74.568 deg which is
    RA(J2000)  =  13h 02m 01.0s
    Dec(J2000) = +74d 34' 04.0"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.

The mask-weighted light curve shows one group of multiple overlapping
peaks from T+40 to T+70.  T90 (15-350 keV) is 17.9 +- 1.7 sec (estimated
error including systematics).

The time-averaged spectrum from T+47.6 to T+67.3 sec is best fit by a
simple power-law model.  The power law index of the time-averaged
spectrum is 1.72 +- 0.19.  The fluence in the 15-150 keV band is
3.1 +- 0.4 x 10^-07 erg/cm2.  The 1-sec peak photon flux measured from
T+63.87 sec in the 15-150 keV band is 0.5 +- 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/414592/BA/


GRB_name: GRB100302A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10463
SUBJECT: GRB 100302A: MASTER-Net  optical alert observations  
DATE:    10/03/03 11:31:50 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

V.Yurkov, S.Sergienko, D.Varda,
Blagoveschensk Educational State University, Blagoveschensk


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

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


V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov Ural State University, Kourovka


K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok
Irkutsk State University


MASTER  robotic telescope (MASTER-Net: http://observ.pereplet.ru, 200
mm, FOV=8 square degrees (testing telescope) and  Very Wide Field Camera 
(D=50 mm, 1000 square  degrees, 11 Mpx, 36" per pix, mounted on telescope)
located at Blagoveschensk   was responted to the  GRB 100302A (Swift Bat  alert,
  Cummings et al, GCN CIRC 10458)   51 sec after  Notice time and  139 s 
after the GRB time.

There is now OT in our images inside Swift XRT error box (Goad et al., GCN
CIRC 10460).



GRB_time     start UT       end UT       t_exp(s)   mlim     Coadd?
-------------------------------------------------------------------

139s          19:55:25      19:55:55       30       16.9       no
139s-4046s    19:55:25      21:14:17     4020       18.5       68


The coadded image  is available at
http://observ.pereplet.ru/images/GRB100302A/GRB_summ.jpg  .
The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100302A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10464
SUBJECT: GRB 100302A: Optical observations at Crni Vrh
DATE:    10/03/03 14:31:32 GMT
FROM:    Bojan Dintinjana at OCV  <bojan.dintinjana@fmf.uni-lj.si>

B. Dintinjana and H. Mikuz on behalf of PIKA observing program at Crni 
Vrh Observatory.

We observed the field of GRB 100302A (Cummings et al., GCN 10458) from 
Crni Vrh Observatory with a 60 cm robotic telescope, R filter and CCD. 
Twenty consecutive exposures of 60 second duration were taken in 
moonlight conditions. First exposure started at 2010-03-02 19:56:20 UT, 
194 seconds after the burst (105 seconds after the SWIFT trigger).

No optical candidate was detected within the uncertainty radius on 
single exposures, having R limiting magnitude 18.3, calibrated against 
the nerby USNO-B R2 magnitude stars. Also we found no optical candidate 
on 20 sumed R images with total exposure of 1200 seconds and limiting R 
band magnitude 19.6 (calibrated against the nerby USNO-B R2 magnitude 
stars).


GRB_name: GRB100302A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10465
SUBJECT: GRB 100302A: Gemini-N OT confirmation
DATE:    10/03/03 15:22:47 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara, D. B. Fox (PSU) report on behalf of
a larger collaboration:

"On March 3.40 UT we observed the field of GRB 100302A (Cummings et
al., GCN 10458) with the Gemini-N telescope and the GMOS spectrograph.

In our 300s i'-band acquisition image we clearly identify a source
inside the XRT refined error circle (Goad et al. 10460).
Using 3 USNO-B1 stars we calibrated our photometry and obtained

i' = 22.01 +- 0.05 mag

This value is significantly below the detection reported by
Huang et al. (GCN 10461) confirming that this is the afterglow
of GRB 100302A.

We also performed a single 1200s spectroscopic observation.
No absorption or emission features have been detected over
the 4000-9000A coverage of our spectrum.

We thank the Gemini staff for performing this observation,
in particular Andrew Stephens."


GRB_name: GRB100302A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10466
SUBJECT: GRB 100302A: Gemini-North redshift
DATE:    10/03/03 16:38:03 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

R. Chornock (Harvard), A. Cucchiara, D. Fox (Penn St.), and E. Berger (Harvard)
report on behalf of a larger collaboration:

Further analysis of the Gemini-North GMOS spectrum of the afterglow (Huang et
al., GCN 10461) of GRB 100302A (Cummings et al., GCN 10458) described in GCN
10465 (Cucchiara et al.) reveals that the afterglow shows a sharp increase in
continuum flux redward of 7100 Angs, with only a weak continuum detected between
5500 and 7000 Angs, consistent with absorption by H I at z~4.8.
There are several narrow absorption features superposed on the noisy red
continuum, consistent with N V, Si II, Si II*, and C II at a mean redshift of
4.813, which we identify as the redshift of this burst.


GRB_name: GRB100302A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10467
SUBJECT: GRB 100302A: Swift-XRT refined analysis
DATE:    10/03/03 17:09:17 GMT
FROM:    Valerio D'Elia at INAF-OAR  <delia@oa-roma.inaf.it>

V. D'Elia, M. Perri (ASDC) and J.R. Cummings (NASA/UMBC) report
on behalf of the Swift-XRT team:

We have analysed the first 3 orbits of Swift-XRT data obtained from
GRB 100302A (trigger 414592; Cummings, et al., GCN Circ. 10458)
from 125 s to 28.8 ks after the BAT trigger.

The best position of the X-ray afterglow is the UVOT enhanced XRT
position given in Goad et al. (GCN Circ. 10460).

The 0.3-10 keV light curve shows a multiple peak structure, with
three main spikes at about T+200, T+250 and T+400s, followed by a
fast decay with index 3.35+-0.3 and by a break at 1ks. Later time
data are fitted by a second power law with a decay index of
0.26+-0.12.

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.28 (-0.15, +0.17). The
best-fitting absorption column is 1.1 (-0.20, +0.17) x 10^21 cm^-2, in
excess of the Galactic value of 1.9 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 3.3 x 10^-11 (4.7 x 10^-11) erg
cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
0.26, the count rate at T+24 hours will be 0.01 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.3 x
10^-13 (4.7 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/00414592.

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


GRB_name: GRB100302A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10468
SUBJECT: GRB 100302A: Swift/UVOT Upper Limits
DATE:    10/03/03 19:04:52 GMT
FROM:    Michele Stark at PSU/Swift  <stark@astro.psu.edu>

M. A. Stark (PSU) and J. R. Cummings (NASA/UMBC) report on behalf of
the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100302A
132 s after the BAT trigger (Cummings et al., GCN 10458). No optical
afterglow consistent with the XRT position (Cummings et al., GCN
10458) is detected in the initial UVOT exposures. We do not see any
source within the XRT error circle that might correspond to the R and
I-band source reported by Huang et al. (GCN 10461) from the Lulin
1-meter telescope or the i' source reported by Cucchiara and Fox (GCN
10465) from Gemini-N.

Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are:

Filter     T_start(s)   T_stop(s)   Exp(s)   Mag
---------------------------------------------------
white_FC   133          282         147      >21.06
white      133          2044        431      >21.24
v          621          1933        156      >18.82
b          547          2032        136      >19.58
u          291          2007        382      >20.10
w1         670          1982        155      >19.49
m2         645          1957        136      >19.26
w2         596          1908        156      >19.61

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the
burst (Schlegel et al. 1998).


GRB_name: GRB100302A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10469
SUBJECT: GRB 100302A: Ondrejov 65cm limit
DATE:    10/03/04 15:24:50 GMT
FROM:    Petr Kubanek at AIO  <pkubanek@gmail.com>

K. Hornoch (Astronomical Institute, Academy of Sciences of the Czech
Republic) & P. Kubanek (IPL UV Valencia & IAA CSIC Granada, Spain)
reports on behalf of a larger collaboration:

We acquired unfiltered CCD images of GRB 100302A XRT error box
(J.R.Cummings, GCN 10458) with Ondrejov 65cm telescope + CCD. AS the CCD
is equipped with IR-block filter its sensitivity in I band is very close to 0.

Observation started March 3 00:40 UT (4h47m after the BAT trigger).
During observation which run till 03:00 UT 45 of 3 minutes exposures were
obtained. On the combined image we do not identify any new object down to 
R ~22 magnitude. Particularly we do not see anything significant at the
proposed OT position (K.Y. Huang, GCN 10461).

This message can be cited


GRB_name: GRB100305A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10470
SUBJECT: GRB 100305A: Swift detection of a burst
DATE:    10/03/05 09:22:05 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

E. Troja (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
J. R. Cummings (NASA/UMBC), A. de Ugarte Postigo (INAF-OAB),
P. A. Evans (U Leicester), J. M. Gelbord (PSU),
O. Godet (U Leicester), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), H. A. Krimm (CRESST/GSFC/USRA),
R. Margutti (Univ Bicocca&OAB), C. Pagani (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU) and
R. L. C. Starling (U Leicester) report on behalf of the Swift Team:

At 09:05:38 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100305A (trigger=414905).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 168.365, +42.376 which is 
   RA(J2000) = 11h 13m 28s
   Dec(J2000) = +42d 22' 34"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a total duration of about 20 sec, starting at ~T+50 
relative to the start of the image trigger interval.  The peak count rate
was ~500 counts/sec (15-350 keV), at ~65 sec after the trigger. 

The XRT began observing the field at 09:07:57.6 UT, 139.2 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 168.36762, 42.40281 which
is equivalent to:
   RA(J2000)  = 11h 13m 28.23s
   Dec(J2000) = +42d 24' 10.1"
with an uncertainty of 4.4 arcseconds (radius, 90% containment). This
location is 96 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
2.14e+20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 4.86e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 122 seconds with the White filter
starting 144 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
0.01. 

Burst Advocate for this burst is E. Troja (eleonora.troja AT 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: GRB100305A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10471
SUBJECT: GRB 100305A: P60 Observations
DATE:    10/03/05 10:48:37 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 GRB100305A (Troja et al., GCN 10470) with the
automated Palomar 60-inch telescope.  Images were obtained in the Sloan
g', r', i', and z' filters beginning at 09:09 UT on 5 March 2010 (~ 3.5
minutes after the burst).

In coadded images, we find no sources inside the XRT error circle to the
following limits (calculated with respect several point sources in the
SDSS DR7 catalog):

Filter  Mid-point t_burst  Exposure Magnitude
-------------------------------------------------------------------------
r'  09:25  19.5 min 720.0  > 22.0
z'  09:27  21.7 min 420.0  > 20.5
i'  09:28  23.3 min 660.0  > 22.0

The lack of an optical afterglow candidate, together with the long
duration and lack of X-ray absorption in excess of the Galactic value
(Troja et al., GCN 10470), make GRB100305A a candidate high redshift
event.  We encourage additional follow-up at longer wavelengths.


GRB_name: GRB100305A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10472
SUBJECT: GRB 100305A: PAIRITEL NIR Upper Limits
DATE:    10/03/05 10:57:48 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

A. N. Morgan, J. S. Bloom, and S. B. Cenko (UC Berkeley) report:

We observed the field of GRB 100305A (Troja et al., GCN 10470) with
the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began
at 2010-03-05 09h29m30s UT, ~0.4 hours after the Swift trigger. In
initial mosaics (effective exposure time of ~795.6 seconds) taken
simultaneously in the J, H, and Ks filters, we do not detect any
sources within the XRT error circle.

The preliminary photometry yields:

post_burst
t_mid(min) exp(s) filt  U. Limit (3 sig)
34.6    795.6  J    > 19.2
34.6    795.6  H    > 18.0
34.6    795.6  Ks   > 17.3

Observations are ongoing. All magnitudes given in the Vega system,
calibrated to 2MASS. No correction for Galactic extinction has been
made to the above reported values.


GRB_name: GRB100305A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10473
SUBJECT: GRB 100305A: Gemini-N OT candidate
DATE:    10/03/05 12:44:33 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara (PSU),  report on behalf of a larger collaboration:

"On March 5.42 UT we observed the field of GRB 100305A (Troja et
al., GCN 10470) with the Gemini-N telescope and the GMOS instrument.

In our 300s r'-band and 900s i'-band images we clearly detect
a source inside the XRT error circle at the following position:

RA (J2000) = 11:13:28.30
Dec (J2000) = 42:24:10.50

with an uncertainty of 0.5" in each coordinate.

Using 2 USNO-B1 stars we calibrated our photometry and obtained

r' = 23.95 +- 0.30 mag
i' = 23.71 +- 0.50 mag

At the moment no evidence of fading can be addressed.
Further analysis are in progress.

We thank the Gemini staff for performing this observation,
in particular Andrew Stephens."


GRB_name: GRB100305A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10474
SUBJECT: GRB 100305A: Enhanced Swift-XRT position
DATE:    10/03/05 13:32:10 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 2448 s of XRT Photon Counting mode data and 6 UVOT
images for GRB 100305A, 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 = 168.36691, +42.40393 which is equivalent
to:

RA (J2000): 11h 13m 28.06s
Dec (J2000): +42d 24' 14.1"

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, MNRAS, 397, 1177).

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


GRB_name: GRB100305A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10475
SUBJECT: GRB 100305A Optical Observations
DATE:    10/03/05 14:57:01 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 imagery of the GRB 100305A burst reported by Troja et al.
(GCN 10470) using the Sonoita Research Observatory (SRO) 35cm telescope
in southern Arizona, utilizing an automatic VOevent trigger.  The
exposures began about 3 minutes after the burst and continued
for approximately two hours.  20 Rc-band, 10 V-band, and a set of
BVRI exposures for field calibration were acquired.
Inspection of the enhanced Swift-XRT position given by Osborne, et al.
(GCN 10474) does not show any optical afterglow to the following limits,
based on using star USNOB 1323-0268523 at 11:13:38.45 +42:23:45.7
as having magnitudes R=15.98 and V=16.67):

UTmid     delT    exp   filt  lim
(hrs)     (min)  (# x s)
09.1544  003.63  01x060  Rc  19.1
09.2379  008.64  10x060  Rc  20.5
09.4821  023.29  05x180  Rc  21.3
09.8411  044.83  05x300  Rc  21.6
10.8564  105.75  10x300  V   21.1

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


GRB_name: GRB100305A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10476
SUBJECT: GRB 100305A: Swift-XRT refined analysis
DATE:    10/03/05 15:54:41 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo, R. Margutti, B. Sbarufatti (INAF-OAB) and E. Troja
(NASA/GSFC/ORAU) report on behalf of the Swift-XRT team:

We have analysed 2.5 ks of the Swift-XRT data for GRB 100305A (Troja
et al. GCN Circ. 10470), from 145 s to 6.0 ks after the  BAT trigger. The
data comprise 84 s in Windowed Timing (WT) mode with the remainder
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. 10474).

Analysis of the light curve shows an initial steep power-law decay with
an index of alpha=3.5 (+/-0.4), followed by a break at T+300 s to an
alpha of 0.84 (+0.11, -0.58).

A spectrum formed from the WT mode data can be fitted with an
absorbed power-law with a photon spectral index of 1.96 (+0.21,-0.20).
The best-fitting absorption column is  1.7 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 2.1 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.14 (+0.24,-0.20)
and a best-fitting absorption column of 1.7 (+0.60, -0.30) x 10^21
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.8 x 10^-11 (5.8 x 10^-11) erg
cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
0.84, the count rate at T+24 hours will be 0.015 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.8 x
10^-13 (8.7 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/00414905.

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


GRB_name: GRB100305A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10477
SUBJECT: GRB 100305A: Swift/UVOT Upper Limits
DATE:    10/03/05 18:24:08 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and E. Troja (NASA/GSFC/ORAU) report on behalf
of the Swift/UVOT team.

The Swift/UVOT began settled observations of the field of
GRB 100305A 144s after the BAT trigger (Troja et al.,
GCN Circ. 10470).  Data summed from the first and second orbits
do not reveal a source at the enhanced position of the X-ray
afterglow (Osborne et al., GCN Circ. 10474) or the candidate
afterglow reported by Cucchiara et al. (GCN Circ. 10473).

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      144        266        120       > 20.60
white        4636       4836        196       > 21.10
v            3612       5247        393       > 19.85
b            4432       6048        373       > 20.68
u            4227       5863        393       > 20.45
uvw1         4022       5656        393       > 20.46
uvm2         3817       5451        393       > 20.2
uvw2         4842       5042        196       > 20.17
=======================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.01 (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: GRB100305A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10478
SUBJECT: GRB 100305A: Gemini z'-band observation
DATE:    10/03/05 19:56:11 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara (PSU), report on behalf of a larger collaboration:

"We continued our observations of GRB 100305A with the Gemini-N
telescope mounted with the GMOS camera.
A sequence of z'-band images has been taken for a total exposure
time of 15 min.

No clear object is visible in the position of the optical afterglow
previously reported (GCN 10473) at the following 3-sigma upper limit:

z' > 23.42 mag

We also report a corrected error measure in our photometry.
The correct magnitude estimates at T0 + 2h are:

r' = 23.95 +- 0.30 mag
i' = 23.71 +- 0.06 mag

We apologize for any inconvenience this may have caused."


GRB_name: GRB100305A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10479
SUBJECT: GRB 100305A, Swift-BAT refined analysis
DATE:    10/03/05 21:51:53 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.krimm@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),
E. Troja (NASA/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 the recent telemetry downlink,
we report further analysis of BAT GRB 100305A (trigger #414905)
(Troja, et al., GCN Circ. 10470).  The BAT ground-calculated position is
RA, Dec = 168.373, 42.381 deg which is
    RA(J2000)  =  11h 13m 29.5s
    Dec(J2000) = +42d 22' 50.7"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 22%.

The mask-weighted light curve shows a broad structure of two overlapping peaks
beginning at T+0 and continuing to T+80 sec with the highest peak at T+60 sec.
There is soft, low-level emission extending to ~T+200 sec. T90 (15-350 keV) is 
69.7 +- 8.7 sec (estimated error including systematics).

The time-averaged spectrum from T-9.2 to T+70.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.27 +- 0.23.  The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-6 
erg/cm^2. The 1-sec peak photon flux measured from T+62.72 sec in the 15-150 keV 
band is 0.9 +- 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/414905/BA/


GRB_name: GRB100302A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10480
SUBJECT: GRB100302A : LOAO observations and Lulin afterglow analysis 
DATE:    10/03/06 02:14:20 GMT
FROM:    Kuiyun Huang at ASIAA  <ljhuang@asiaa.sinica.edu.tw>

GRB100302A : LOAO observations and Lulin afterglow analysis

K.Y. Huang (ASIAA), Myungshin Im (CEOU/Seoul National Univ) and
Y. Urata (NCU) on behalf of EAFON team :

We observed GRB100302A afterglow position (Goad et al. GCN 10460,
Huang et al. GCN 10461 and Cucchiarar & Fox GCN 10465) in i-band
(12x300s) using 1.0 telescope at Mt. Lemmon (Arizona, US) operated by
the Korea Astronomy Space Science Institute.

No significant detection of afterglow in our i-band combined image at
11.0709 hours after the burst. The 3-sigma limiting magnitude is 20.8,
which calibrated with five nearby USNOB stars.

We also reduced R and i band images taken by Lulin 1-m telescopes. Our
photometric results, combined with the i-band detection reported by
Cucchiarar & Fox (GCN 10465), indicate the i-band power law index is
about -0.65.

Delay time    filter   EXPTIME    Magnitude   error
   (hour)
---------------------------------------------------
   0.450        R       300s x 5   21.54      0.22
   0.780        I        300s      20.02      0.12
   0.873        I        300s      20.24      0.15
   0.966        I        300s      20.08      0.13
   1.060        I        300s      20.17      0.17
   1.153        I        300s      20.34      0.19
   1.357        I      300s x 4    20.31      0.17
--------------------------------------------------

This  message can be cited


GRB_name: GRB100305A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10481
SUBJECT: GRB 100305A: Super-LOTIS early observations
DATE:    10/03/09 01:04:25 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike (Clemson University), Peter A. Milne (Steward
Observatory), G. Grant Williams (MMTO), and Dieter H. Hartmann (Clemson
University) report:

We observed the field of GRB 100305A (Troja et al., GCN 10470) with the
0.6m Super-LOTIS telescope located at Kitt Peak National Observatory
beginning 106 seconds after the trigger.  Observations were
carried out in the R band for approximately 45 minutes under good
conditions.  We do not detect any sources within the XRT enhanced error
circle (Osborne et al., GCN 10474) or the source detected by Gemini-N
(Cucchiara, GCN 10473).

Band  Exptime  co-adds  time    UL
-------------------------------------
R      10        5      106    > 17.5
R      20        5      202    > 19.2
R      60       30      389    > 20.5


Exptime is given in seconds; time is seconds after trigger of first
observation.  All limits given relative to USNO B1.0 field stars.


GRB_name: GRB100305A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10482
SUBJECT: GRB100305A: Optical upper limits at IAO
DATE:    10/03/12 13:19:52 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>

D. Kuroda (OAO, NAOJ),  H. Hanayama, T. Miyaji, J. Watanabe(IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 100305A (Troja et al. GCNC 10470)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.

The observation started on 2010-03-05 13:03:55 UT (~4h after the
burst). We did not find any new point source in the XRT error
circle (Osborne et al., GCNC 10474) in all the three bands.

Three sigma upper limits of the OT are listed below. We used
SDSS catalog for flux calibration.

T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.18816    13:36:35  3300.0      >22.1  >21.6  >20.4
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]


GRB_name: GRB100316A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10484
SUBJECT: GRB 100316A: Swift detection of a burst
DATE:    10/03/16 02:35:00 GMT
FROM:    Wayne Baumgartner at GSFC  <wayne@milkyway.gsfc.nasa.gov>

W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC), E. Troja (NASA/GSFC/ORAU),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 02:23:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100316A trigger=416076).  The BAT on-board calculated location is 
RA, Dec 252.032, +71.825 which is 
   RA(J2000) = 16h 48m 08s
   Dec(J2000) = +71d 49' 31"
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 10 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~2 sec after the trigger. 

Due to an observing constraint, Swift will not slew until 
T0+51.8 minutes. There will be no XRT or UVOT data until
this time. 

Burst Advocate for this burst is W. H. Baumgartner (wayne 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: GRB100316A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10485
SUBJECT: GRB 100316A: Swift-XRT detection
DATE:    10/03/16 04:12:35 GMT
FROM:    Andy Beardmore at U Leicester  <apb@star.le.ac.uk>

A.P. Beardmore, K.L. Page and O. Littlejohns (U. Leicester) report
on behalf on the Swift-XRT team:

Using 2.4ks of promptly downlinked data starting at 51.8 minutes after 
the trigger we find an uncatalogued X-ray
source located at RA, Dec = 251.9789, 71.8265
which is equivalent to:

RA  (J2000) =  16 47 54.94
DEC (J2000) =  +71 49 35.3

with an uncertainty of 4.53 arcsec (radius, 90% containment).

It is not possible to tell whether the source is fading
with the limited data available so far.


GRB_name: GRB100316A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10486
SUBJECT: GRB 100316A: Swift/UVOT Observations
DATE:    10/03/16 04:16:17 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and W. H. Baumgartner (GSFC/UMBC) report on behalf  
of the
Swift/UVOT team:

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 3200 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 (Beardmore et al., GCN Circ. 10485). 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 0.03.


GRB_name: GRB100316A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10487
SUBJECT: GRB 100316 optical candidate from 1.23m CAHA telescope
DATE:    10/03/16 04:22:03 GMT
FROM:    Javier Gorosabel at IAA-CSIC  <jgu@iaa.es>

J. Gorosabel (IAA-CSIC), V. Peris (U. Valencia), P. Kubanek (IAA-CSIC,
U. Valencia), report on behalf of a larger collaboration:

"We have  carried out R-band  observations of the GRB100316  BAT error
box (Baumgartner et  al., GCN 10484) with the  1.23m telescope of Calar
Alto.  The observations started on  March 16.1075 UT (11.7 min after the
GRB).  We detect an object with a rough magnitude of R~20.5 coincident
with the  XRT (GCN 10485) position and  very likely  not  present on  the 
DSS.   Further observations  are   encouraged  to  determine   the 
possible  fading behaviour  of this  source.  We  propose  that object  as
the potential optical afterglow of GRB100316."

[GCN OPS NOTE(16mar10): Per author's request, the "Feb 16.1075" was changed
to "March 16.1075".]


GRB_name: GRB100316A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10488
SUBJECT: GRB 100316 optical candidate from 1.23m CAHA telescope
DATE:    10/03/16 05:16:37 GMT
FROM:    Javier Gorosabel at IAA-CSIC  <jgu@iaa.es>

J. Gorosabel (IAA-CSIC), V. Peris (U. Valencia), P. Kubanek (IAA-CSIC,
U. Valencia), report on behalf of a larger collaboration:

"We have  carried out R-band  observations of the GRB100316  BAT error
box (Baumgartner et  al., GCN 10484) with the  1.23m telescope of Calar
Alto.  The observations started on  Feb 16.1075 UT (11.7 min after the
GRB).  We detect an object with a rough magnitude of R~20.5 coincident
with the  XRT (GCN 10485) position and  very likely  not  present on  the 
DSS.   Further observations  are   encouraged  to  determine   the 
possible  fading behaviour  of this  source.  We  propose  that object  as
the potential optical afterglow of GRB100316."


GRB_name: GRB100316B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10489
SUBJECT: GRB 100316B: Swift detection of a burst with optical counterpart
DATE:    10/03/16 08:15:37 GMT
FROM:    Wayne Baumgartner at GSFC  <wayne@milkyway.gsfc.nasa.gov>

W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
S. Campana (INAF-OAB), P. A. Evans (U Leicester), J. M. Gelbord (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
O. M. Littlejohns (U Leicester), V. Mangano (INAF-IASFPA),
C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester),
C. Pagani (U Leicester), K. L. Page (U Leicester),
P. Romano (INAF-IASFPA), A. Rowlinson (U Leicester),
M. H. Siegel (PSU), R. L. C. Starling (U Leicester),
G. Tagliaferri (INAF-OAB) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 08:01:36 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100316B trigger=416103).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is RA, Dec 163.498, -45.480 which is 
   RA(J2000) = 10h 54m 00s
   Dec(J2000) = -45d 28' 47"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 5 sec.  The peak count rate
was ~2500 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 08:02:41.1 UT, 64.1 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 163.48846, -45.47220 which
is equivalent to:
   RA(J2000)  = 10h 53m 57.23s
   Dec(J2000) = -45d 28' 19.9"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 36 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
9.92e+20 cm-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 66 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 10:53:57.15 = 163.48812
  DEC(J2000) = -45:28:21.6  = -45.47267
with a 90%-confidence error radius of about 0.62 arc sec. This position is 2.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.36 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.14. 

Burst Advocate for this burst is W. H. Baumgartner (wayne 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: GRB100316A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10490
SUBJECT: GRB 100316A: Enhanced Swift-XRT position
DATE:    10/03/16 08:21:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans reports on behalf of the Swift-XRT team

Using 1129 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 = 251.98150, 71.82780 which is equivalent to:

RA (J2000):  16 47 55.56
Dec (J2000): +71 49 40.0

with an uncertainty of 2.9 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, MNRAS, 397, 1177).

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


GRB_name: GRB100316C
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10491
SUBJECT: GRB 100316C: Swift detection of a burst
DATE:    10/03/16 09:12:15 GMT
FROM:    Michael Stamatikos at OSU/GSFC  <michael.stamatikos-1@nasa.gov>

M. Stamatikos (OSU/NASA/GSFC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
P. A. Evans (U Leicester), J. M. Gelbord (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
O. M. Littlejohns (U Leicester), R. Margutti (Univ Bicocca&OAB),
C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester),
C. Pagani (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (INAF-IASFPA), M. H. Siegel (PSU),
R. L. C. Starling (U Leicester) and L. Vetere (PSU) report on behalf
of the Swift Team:

At 08:57:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100316C trigger=416115).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 32.291, -68.009 which is 
   RA(J2000) = 02h 09m 10s
   Dec(J2000) = -68d 00' 31"
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 7 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 08:59:17.9 UT, 78.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 32.2869, -67.9914 which
is equivalent to:
   RA(J2000)  = 02h 09m 8.85s
   Dec(J2000) = -67d 59' 29.1"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 63 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.94e+20
cm-2, Kalberla et al. 2005), with an excess column of 2.6
(+2.05/-1.79) x 1021 cm-2 (90% confidence). 

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 3-sigma upper limit has been about 19.6 mag. 
The overlap of the 8'x8' region for the list of sources generated on-board and
the BAT error circle is uncertain. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.04. 

Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT 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: GRB100316B
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10493
SUBJECT: GRB 100316B: GROND Detection of the Optical/NIR Afterglow Candidate
DATE:    10/03/16 10:11:25 GMT
FROM:    Robert Filgas at MPI  <filgas@mpe.mpg.de>

P. Afonso, R. Filgas and J.Greiner (all MPE Garching) report on behalf of
the GROND team:

We observed the field of GRB 100316B (Swift trigger #416103; Baumgartner
et al., GCN #10489) 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 08:17 UT on 16 March 2010, 16 minutes after the
GRB trigger, and are continuing.

We detect a single point source within the UVOT error circle reported by
Baumgartner et al.

Based on the first 4 min of total exposures in g'r', we estimate
preliminary magnitudes (all in AB system) of

g' = 19.2 +- 0.1 mag,

r' = 18.9 +- 0.1 mag,

indicating reshift < 3.5.

Given magnitudes are calibrated against GROND zeropoints and are not
corrected for the expected Galactic foreground extinction corresponding to
a reddening of E_(B-V)=0.14 mag in the direction of the burst (Schlegel et
al. 1998).


GRB_name: GRB100316B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10494
SUBJECT: GRB 100316B: Skynet/PROMPT Observations of Fading
DATE:    10/03/16 10:13:19 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, K. Ivarsen, D. Reichart, A. LaCluyze, R. Egger, A. Foster, J. 
Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. 
Nysewander report:

Skynet observed the Swift/BAT localization of GRB 100316B (Baumgartner et 
al., GCN 10489) with four of the 16" PROMPT telescopes at CTIO beginning 32 
seconds after the trigger (19 seconds after notification) in BVRI.

We detect the afterglow (Baumgartner et al., GCN 10489) in all filters.

At 34 seconds after the trigger, the afterglow's magnitude was I = 15.61 
+0.16 -0.14 (statistical) +/- 0.20 (systematic; calibrated to 56 USNO B1 
stars).

Between 34 seconds and 2.1 minutes after the trigger, the afterglow faded 
with a power-law index of about -1.0.

Between 2.1 and 35 minutes after the trigger, the afterglow faded more 
slowly, with a power-law index of about -0.3.

Between 35 and 41 minutes after the trigger, the afterglow suddenly 
rebrightened, with a power-law index of about +5.4.

Between 41 and 49 minutes after the trigger, the afterglow faded with a 
power-law index of about -0.6.

Between 49 and 95 minutes after the trigger, the afterglow faded more 
rapidly, with a power-law index of about -1.7.

At 95 minutes after the trigger, the afterglow's magnitude was R = 19.51 
+0.33 -0.26 (statistical) +/- 0.28 (systematic; calibrated to 40 USNO B1 
stars).

Skynet's most recent BVRI light curve, calibrated to USNO B1 and NOMAD 
stars, can be found here:

http://skynet.unc.edu/grb/grb100316b.png


GRB_name: GRB100316B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10495
SUBJECT: GRB 100316B: VLT/X-shooter redshift
DATE:    10/03/16 11:04:59 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

S.D. Vergani (APC/Univ. Paris 7), P. D'Avanzo (INAF-OAB), D. Malesani, 
J.P.U. Fynbo, J. Hjorth (DARK/NBI), A.J. Levan (Univ. Warwick), H. Flores
(Paris Obs.), N.R. Tanvir (Univ. Leicester), P. Goldoni (APC/Univ. Paris 7
and SAp/CEA), L.A. Antonelli (INAF-OAR) report on behalf of a larger
collaboration:

We observed the optical afterglow of GRB 100316B (Baumgartner et al., GCN
10489; Afonso et al. GCN 10493; Haislip et al., GCN 10494) with the VLT
equipped with the X-shooter spectrograph. Observations started on 2010 Mar
16 at 08:43 UT (~ 40 minutes after the GRB), for a total exposure time of
4x600 s. From the acquisition image, we estimate for the optical afterglow
a magnitude of R = 18.2 +- 0.1 (calibrated against USNO-B1.0).
In a preliminary analysis of the specta, we clearly detect the continuum
in the UVB, VIS, and NIR arms, corresponding to the wavelength range
3200-24000 AA. We detect several absorption features, among these
FeII(1608), AlII(1670), AlIII(1854), FeII(2344), FeII(2374), FeII(2382),
MgII(2796, 2803) and MgI(2852) at a common redshift of z=1.180. The lack
of Lyman forest lines down to ~3200 AA sets an upper limit to the redshift
z<1.6. We also find evidence for FeII lines and MgII doublet from a strong
intervening systems at z=1.063.

We caution that the above analysis (particularly the wavelength solution)
is preliminary. Reduction with updated calibrations is underway. We would
like to thank the ESO staff for their kind assistance, in particular Linda
Schmidtobreick, Christophe Martayan, Patricia Guajardo and Manuel
Olivares.


GRB_name: GRB100316D
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10496
SUBJECT: GRB 100316D: Swift detection of a burst
DATE:    10/03/16 12:56:50 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. Stamatikos (OSU/NASA/GSFC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
S. Campana (INAF-OAB), A. de Ugarte Postigo (INAF-OAB),
P. A. Evans (U Leicester), J. M. Gelbord (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
R. Margutti (Univ Bicocca&OAB), F. E. Marshall (NASA/GSFC),
S. R. Oates (UCL-MSSL), C. Pagani (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA),
R. L. C. Starling (U Leicester) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 12:44:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100316D trigger=416135).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 107.615, -56.278 which is 
   RA(J2000)  =  07h 10m 28s
   Dec(J2000) = -56d 16' 40"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  This is an image trigger, but there is a
possibility that there is a low-level peak about 100 sec long. 

The XRT began observing the field at 12:47:08.1 UT, 137.7 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 107.6291, -56.2567 which is equivalent to:
   RA(J2000)  = 07h 10m 30.98s
   Dec(J2000) = -56d 15' 24.1"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 81 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 2.38e-09 erg cm-2 s-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 148 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Because part of the 2.7'x2.7'
sub-image was not received, the overlap with the XRT error circle is uncertain. 
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 0.12. 

Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT 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: GRB100316C
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10497
SUBJECT: GRB 100316C: BOOTES-3 observations
DATE:    10/03/16 13:30:41 GMT
FROM:    Martin Jelinek at Inst.Astrophys.Andalucia,Granada  <mates@iaa.es>

M. Jelinek (IAA-CSIC), A. de Ugarte Postigo (INAF-OAB),
A.J. Castro-Tirado (IAA-CSIC), J. Gorosabel (IAA-CSIC),
P. Kubanek (IPL UV, IAA-CSIC), R. Cunniffe (IAA-CSIC),
S. Guziy (IAA-CSIC), P. Yock  (Auckland Univ.),
W.H. Allen (Vintage Lane Obs.), I. Bond (Massey Univ.),
G. Christie (Stardome Obs.),
on behalf of a larger collaboration report:

"We have observed the field of GRB 100316C (Stamatikos et al.,
GCN 10491) using the 0.6m Yock-Allen robotic telescope
(BOOTES-3) located in Blenheim, New  Zealand.  Observations
began at  8:58:47 UT (49s from GRB onset and 4 s from the GCN
alert receipt).  We do not detect any  source within the XRT
error circle in a 20 x 2 second combined unfiltered image down
to a 3 sigma limiting magnitude of 18.5."


GRB_name: GRB100316A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10499
SUBJECT: GRB100316A: Swift/UVOT Upper Limits
DATE:    10/03/16 14:30:44 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

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

The Swift/UVOT began settled observations of the field of
GRB 100316A 3201s after the BAT trigger (Baumgartner et al., GCN Circ.  
10484).
We do not detect any source at the enhanced Swift XRT position
(Evans et al. GCN Circ. 10490) and at the location of the candidate  
source detected
by the CAHA telescope (Gorosabel et al. GCN Circ. 10487).

The 3-sigma upper limits for the finding chart exposures (FC)
and summed images are:

Filter   T_start   T_stop   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white (FC) 3201     3350     147     > 21.08
white      3770     5408     393     > 21.32
v          4182     16726    1210    > 20.48
b          3565     5203     393     > 20.79
u          3359     11527    1110    > 20.66
uvw1       4593     10786    1082    > 21.11
uvm2       4387     17306    1648    > 21.11
uvw2       3977     15812    1279    > 21.28
-------------------------------------------------------------

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: GRB100316B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10500
SUBJECT: GRB 100316B: Swift-BAT refined analysis 
DATE:    10/03/16 15:54:41 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), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 100316B (trigger #416103)
(Baumgartner, et al., GCN Circ. 10489).  The BAT ground-calculated position is
RA, Dec = 163.499, -45.464 deg, which is 
   RA(J2000)  =  10h 53m 59.8s 
   Dec(J2000) = -45d 27' 49.3" 
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.
 
The mask-weighted light curve shows a FRED peak starting at T-0.3 sec,
peaking at ~T+0.2 sec, and ending at ~T+20 sec.  T90 (15-350 keV) is
3.8 +- 0.5 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.4 to T+4.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.23 +- 0.18.  The fluence in the 15-150 keV band is 2.0 +- 0.2 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T-0.11 sec in the 15-150 keV band
is 1.3 +- 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/416103/BA/


GRB_name: GRB100316A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10501
SUBJECT: GRB 100316A: Swift-BAT refined analysis
DATE:    10/03/16 16:03:52 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),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), 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 100316A (trigger #416076)
(Baumgartner, et al., GCN Circ. 10484).  The BAT ground-calculated position is
RA, Dec = 251.953, 71.819 deg which is 
   RA(J2000)  =  16h 47m 48.8s 
   Dec(J2000) = +71d 49' 09.5" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 16%.
 
The mask-weighted light curve shows a FRED-like pulse starting at ~T-1 sec,
peaking at ~t+2 sec, and ending at ~T+20 sec.  T90 (15-350 keV) is
7.0 +- 0.9 sec (estimated error including systematics).
 
The time-averaged spectrum from T-1.2 to T+6.7 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.46 +- 0.18.  The fluence in the 15-150 keV band is 8.2 +- 0.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+1.94 sec in the 15-150 keV band
is 2.3 +- 0.4 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/416076/BA/


GRB_name: GRB100316B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10502
SUBJECT: GRB 100316B: Enhanced Swift-XRT position
DATE:    10/03/16 16:51:19 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 1148 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 100316B, 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 = 163.48865, -45.47244 which is equivalent
to:

RA (J2000): 10h 53m 57.28s
Dec (J2000): -45d 28' 20.8"

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, MNRAS, 397, 1177).

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


GRB_name: GRB100316A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10503
SUBJECT: GRB 100316A: Swift-XRT refined analysis
DATE:    10/03/16 17:21:12 GMT
FROM:    Andy Beardmore at U Leicester  <apb@star.le.ac.uk>

A. P. Beardmore (U. Leicester) and W. H. Baumgartner (GSFC/UMBC) report
on behalf of the Swift-XRT team:

Due to an Earth-limb constraint, Swift performed a delayed slew to GRB 
100316A (Baumgartner et al. GCN Circ. 10484), with XRT observations 
starting 3.2 ks after the BAT trigger. The enhanced XRT position for this 
burst was given by Evans (GCN. Circ 10490).

The X-ray light curve, obtained from 7.5 ks of Photon Counting (PC)
mode data spanning 3.2 ks to 17.3 ks after the trigger, can be
modelled by a power-law decay, with a decay slope of 1.3 +/- 0.3.

An X-ray spectrum formed from the same data can be modelled by an
absorbed power-law, with a photon index of 2.3 +0.3 -0.5 and absorbing
column density of (1.5 +1.2 -1.1) x 10^21 cm^-2, which is in excess of
the Galactic value of 4.4 x 10^20 cm^-2 (Kalberla et al. 2005) in the
direction of the source. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (5.3
x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay at the same rate, the count rate
at T+24 hours will be 1.2 x 10^-3 count s^-1, corresponding to an
observed (unabsorbed) 0.3-10 keV flux of 4.0 x 10^-14 (6.3 x 10^-14)
erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00416076.

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


GRB_name: GRB100316A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10504
SUBJECT: GRB 100316A: TAROT Calern observatory optical observations
DATE:    10/03/16 18:09:07 GMT
FROM:    Bruce Gendre at ASDC  <bruce.gendre@asdc.asi.it>

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

We imaged the field of GRB 100316A detected by SWIFT
(trigger 416076, GCN 10484, Baumgartner et al. ) with the TAROT robotic 
telescope (D=25cm)
located at the Calern observatory, France.

The observations started 1323s after the GRB trigger
(1299s after the notice). The elevation of the field increased from
58 degrees above horizon and weather conditions were good.

We obtained 16 image with clear filter and 8 images with R filter
(see the description in Klotz et al., 2006, A&A 451, L39).

We do not detect any OT within the exposures. Co-adding the images taken
with clear filter, we can set a limiting magnitude of:

R > 20.0 between t0+1323s to t0+3327s

at the position of the candidate reported by Gorosabel et al. (GCN 10487)
and Beardmore et al. (GCN 10485).


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

N.B. Galactic coordinates are lon=103.8139 lat=+35.1341
and the galactic extinction in R band is 0.1 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.


GRB_name: GRB100316D
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10505
SUBJECT: GRB 100316D: Swift XRT refined analysis
DATE:    10/03/16 18:32:59 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1@star.le.ac.uk>

R.L.C. Starling, P.A. Evans (U. Leicester) and M. Stamatikos (OSU/NASA/GSFC) 
report on behalf of the Swift-XRT team:

We have analysed the first orbit of Swift XRT data for GRB 100316D (Stamatikos 
et al. GCN Circ. 10496), comprising 593 s of exposure
from 143 s to 737 s after the BAT trigger. The data are solely in
Windowed Timing (WT) mode. The light curve over this time decays very 
slowly and can be modelled with a power-law with a decay index of
alpha=0.13+/-0.03.

A spectrum formed from these data can be fitted with an absorbed power-law with 
a photon spectral index of 1.42 (+/-0.04). The best-fitting absorption column 
is 5.9 (+/-0.3) x 10^21 cm^-2, in excess of the Galactic value of 7.0 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 6.6 x 10^-11 
(8.7 x 10^-11) erg cm^-2 count^-1.

If the decay contines with alpha=0.13, the predicted count rate at T+24h 
is 16 count s^-1 or an observed (unabsorbed) 0.3-10 keV flux of 1.1 (1.4) 
x10^-9 erg cm-2 s-1.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_products/00416135.

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


GRB_name: GRB100316C
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10506
SUBJECT: GRB 100316C: Enhanced Swift-XRT position
DATE:    10/03/16 18:52:07 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 1879 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 100316C, 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 = 32.28660, -67.99098 which is equivalent
to:

RA (J2000): 02h 09m 8.78s
Dec (J2000): -67d 59' 27.5"

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, MNRAS, 397, 1177).

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


GRB_name: GRB100316C
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10507
SUBJECT: GRB 100316C: Swift-XRT team refined analysis 
DATE:    10/03/16 19:15:43 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page (U. Leicester) and M. Stamatikos (OSU/NASA/GSFC) report on 
behalf of the Swift-XRT team:

We have analysed 5.7 ks of XRT data for GRB 100316C (Stamatikos et al. GCN 
Circ. 10491), from 87 s to 13.5 ks after the BAT trigger. The data are 
entirely in Photon Counting (PC) mode. The enhanced XRT position for this 
burst was given by Evans et al. (GCN Circ. 10506).

The light curve can be modelled with a doubly-broken power-law, with 
alpha1 = 0.28 (+0.66,-1.18) until T = 258 (+87/-66) s after the trigger, 
at which point the decay steepens to alpha2 = 2.53 (+1.18, -0.44). At T = 
883 (+1857, -271) s, the decay flattens to alpha3 = 0.76 (+0.27, -0.26).

A spectrum formed from the PC mode data can be fitted with an absorbed 
power-law with a photon spectral index of 1.6 (+0.5, -0.4). The best-fitting 
absorption column is 1.8 (+1.6, -1.3) x 10^21 cm^-2, in excess of the Galactic 
value of 3.9 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 
5.1 x 10^-11 (6.2 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of 0.76, the 
count rate at T+24 hours will be 0.0013 count s^-1, corresponding to an 
observed (unabsorbed) 0.3-10 keV flux of 6.6 x 10^-14 (8.1 x 10^-14) erg cm^-2 
s^-1.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_products/00416115.

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


GRB_name: GRB100316B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10508
SUBJECT: GRB 100316B: Swift/UVOT observations
DATE:    10/03/16 19:29:42 GMT
FROM:    Patricia Schady at MSSL/Swift  <msslba@googlemail.com>

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

The Swift/UVOT began observerving the field of GRB 100316B 67s
after the BAT trigger (Baumgartner et al., GCN Circ. 10489). We detect the
optical afterglow in the white, v, b, u and marginally in the uvw1 filter.
The refined UVOT position is RA (J2000)= 163.48809, DEC (J2000)=-45.47265,
which is equivalent to:

     RA (J2000) = 10:53:57.141
    Dec (J2000) = -45:28:21.54

with an estimated uncertainty of 0.52 arcsec (radius, 90% confidence).
This position is consistent with the XRT refined position (Beardmore
et al., GCN Circ 10502). The marginal detection in the uvw1 filter is
consistent with
the VLT redshift upper limit (D'Avanzo et al., GCN Circ. 10495).


Preliminary magnitudes and the 3 sigma upper limits are reported below for
individual optical images and summed UV images.

Filter    T_start(s)  T_stop(s)  Exposure      Mag  Err
###########################################################
white     67           216         147         18.36 +/- 0.05
white     857          1007        147         19.15 +/- 0.09
u   279          528         246         18.44 +/- 0.10
v         1212         1232        19          18.28 +/- 0.46
b         535          555         19          18.97 +/- 0.36
uvw1   659          1108        58          18.91 +/- 0.36
uvm2      634          1246        66          > 18.59
uvw2      585          1207        78          > 19.13
###########################################################

The above magnitudes are not corrected for the Galactic extinction
corresponding to a non-negligible reddening of E_{B-V} = 0.14 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: GRB100316C
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10509
SUBJECT: GRB 100316C: Swift-BAT refined analysis
DATE:    10/03/16 20:04:22 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), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), T. Sakamoto (GSFC/UMBC), 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 recent telemetry downlinks,
we report further analysis of BAT GRB 100316C (trigger #416115)
(Stamatikos, et al., GCN Circ. 10491).  The BAT ground-calculated position is
RA, Dec = 32.309, -67.992 deg which is 
   RA(J2000)  =  02h 09m 14.2s 
   Dec(J2000) = -67d 59' 30.3" 
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows a roughly symmetric peak starting
at ~T-3 sec, peaking at ~T+3 sec, and ending at ~T+12 sec.  T90 (15-350 keV)
is 9.3 +- 1.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-3.0 to T+7.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.58 +- 0.26.  The fluence in the 15-150 keV band is 1.8 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+2.12 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/416115/BA/


GRB_name: GRB100316C
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10510
SUBJECT: GRB100316C: Swift/UVOT Upper Limits
DATE:    10/03/16 20:05:15 GMT
FROM:    Patricia Schady at MSSL/Swift  <msslba@googlemail.com>

S. R. Oates (MSSL-UCL) and M. Stamatikos (OSU/NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 100316C 81s after the BAT trigger (Stamatikos et al., GCN Circ. 10491).
We do not detect any source at the enhanced Swift XRT position
(Evans et al. GCN Circ. 10506).

The 3-sigma upper limits for the finding chart exposures (FC)
and summed images are:

Filter   T_start   T_stop   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white (FC)  81    231        147       > 20.52
white       521   7450       677       > 21.63
u     (FC)  239   489        246       > 19.87
u           644   7039       529       > 20.22
v           570   12991      1326      > 20.45
b           495   7245       549       > 20.72
uvw1        620   6834       333       > 20.24
uvm2        595   13530      741       > 20.60
uvw2        546   7656       471       > 20.57
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.04 mag.
All photometry is on the UVOT photometric system described in Poole et
al. (2008, MNRAS, 383, 627).


GRB_name: GRB100316D
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10511
SUBJECT: GRB 100316D: Swift-BAT refined analysis
DATE:    10/03/16 23:16:32 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), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), 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 telemetry downlinks,
we report further analysis of BAT GRB 100316D (trigger #416135)
(Stamatikos, et al., GCN Circ. 10496).  The BAT ground-calculated position is
RA, Dec = 107.599, -56.275 deg, which is 
   RA(J2000)  =  07h 10m 23.8s 
   Dec(J2000) = -56d 16' 28.9" 
with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.
 
The mask-weighted light curve is relatively flat.  The emission started
before T-80 sec when the location came into the BAT FoV during a
Swift planned-target slew.  Using the event-by-event data, the lightcurve
conitinue through the 64-sec integration of the image trigger and out to
at least T+240 sec.  Using the on-board mask-weighted lightcurve,
the lightcurve continues out to at least T+740 sec where the data ends.
 
The time-averaged spectrum using just the T+0.0 to T+64.0 sec image-trigger
interval is best fit by a simple power-law model.  The power law index of the
time-averaged spectrum is 2.29 +- 0.41.  The fluence in the 15-150 keV band
is 3.0 +- 0.8 x 10^-7 erg/cm2.  The 1-sec peak photon flux measured
from T+0.00 sec in the 15-150 keV band is 0.1 +- 0.0 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/416135/BA/

We note that this lightcurve is very non-typical for a GRB and that
the spectrum is soft.  This is similar both in the temporal and spectral
properties to the GRB060218-SN2006aj burst (Camapana, et al.; Nature,
v224, p1008, Figure 1).  In the 060218 burst, the BAT lightcurve was flat
from T-50 to T+300 sec.  The X-ray temporal decay (Starling, GCN Circ 10505)
is shallow as it was in SN2006aj (Campana, Fig 1).  We further note
that the 5 arcsec XRT error circle (GCN 10496) covers the edge
of an extended object (a pair of unresolved stars or a galaxy) in DSS.


GRB_name: GRB100316D
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10512
SUBJECT: GRB 100316D: VLT/X-shooter observations
DATE:    10/03/17 03:05:25 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

S.D. Vergani (GEPI-Obs. Paris), P. D'Avanzo (INAF-OAB), A.J. Levan (Univ.
Warwick), S. Covino (INAF-OAB), D. Malesani, J. Hjorth (DARK/NBI), L.A.
Antonelli (INAF-OAR) report on behalf of a larger collaboration:

We observed the field of GRB 100316D (Stamatikos et al., GCN 10496) with
the VLT equipped with the X-shooter spectrograph. Observations started on
2010 Mar 17 at 00:58 UT (~ 12 hours after the GRB). In the 100s
acquisition image, we detect an object inside the XRT error circle, at the
following position (J2000):

RA: 07:10:30.77
Dec: -56:15:20.7

(+/- 0.5"). The object has a magnitude R~21 (calibrated against USNO-B1.0)
and is very close (~3.5") to the DSS galaxy reported by Sakamoto et al.
(GCN 10511). In the X-shooter spectrum of this source we detect several
bright emission lines. Among these we have [OII], Hdelta, Hgamma, Hbeta,
[OIII], Halpha all at a common redshift of 0.059. At present, we cannot
say if this object (that might be a region of the nearby galaxy) is
related with GRB 100316D. Further analysis and observations are in
progress.

We caution that the above analysis (particularly the wavelength solution)
is preliminary. Reduction with updated calibrations is underway. We would
like to thank the ESO staff for their kind assistance, in particular
Thomas Rivinius, Alvaro Alvarez and Andres Pino


GRB_name: GRB100316D
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10513
SUBJECT: GRB 100316D: Gemini/GMOS and VLT/X-shooter observations
DATE:    10/03/17 04:37:46 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

S.D. Vergani (GEPI-Obs. Paris), A.J. Levan (Univ. Warwick), P. D'Avanzo
(INAF-OAB), S. Covino (INAF-OAB), D. Malesani, J. Hjorth (DARK/NBI), N.R.
Tanvir (Univ. Leicester), L.A. Antonelli (INAF-OAR) report on behalf of a
larger collaboration:

We carried out further observations of the field of GRB 100316D
(Stamatikos et al., GCN 10496) with the Gemini telescope equipped with
GMOS in imaging mode (~ 12 hours after the GRB). Inside the XRT error
circle we detect two discrete, compact objects, both of which lie on the
stellar field of the DSS galaxy (Sakamoto et al. GCN 10511; Vergani et al.
GCN 10512):

Object A:
RA (J2000): 07:10:30.77
Dec (J2000): -56:15:20.7

Object B:
RA (J2000): 07:10:30.48
Dec (J2000): -56:15:22.3

Both position have errors of approximately 0.5" in each axis. We note that
object "A" is the same reported by Vergani et al. (GCN 10512). We obtained
a VLT/X-shooter spectrum of source "B", which exhibits the same emission
lines reported by  Vergani et al. (GCN 10512) for object "A" at the same
redshift of z=0.059. Likely, object "A" and "B" are regions of the nearby
DSS galaxy.

A finding chart is available at the following web page:
http://www.astro.ku.dk/~malesani/GRB/100316D/GRB100316D_finder.png

We caution that the above analysis (particularly the wavelength solution)
is preliminary. Reduction with updated calibrations is underway. We would
like to thank the Gemini staff for their kind assistance, in particular
Rodrigo Carrasco.


GRB_name: GRB100316D
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10514
SUBJECT: GRB 100316D: GROND Detection of the Optical/NIR Afterglow Candidate
DATE:    10/03/17 04:47:13 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Paulo Afonso (MPE Garching), Adria Updike (Clemson University), Marco
Nardini, Robert Filgas, Abdullah Yoldas, and Jochen Greiner (MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 100316D (Swift trigger 416135; Stamatikos et
al., GCN 10496) 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 00:28 UT on March 17, 11.66 hours after the GRB
trigger, and are continuing. They were performed at an average seeing of
1" and at an average airmass of 1.1.

We detect what appears to be a bright point on the edge of the extended
object noted by Sakamoto et al. (GCN 10511) within the XRT error circle. 
This is consistent with the source identified by Vergani et al. (GCN
10512).  The source is detected in all bands, suggesting a redshift < 3.5.
 We cannot yet determine if this source is related to the GRB.

Further observations are required to establish variability, and to check
whether the optical bands show similarities to GRB 060218 - SN 2006aj as
reported by Sakamoto et al. (GCN 10511) for the gamma ray and x-ray bands.


GRB_name: GRB100316C
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10516
SUBJECT: GRB 100316C: GROND Detection of a Optical/NIR Afterglow Candidate
DATE:    10/03/17 05:41:37 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Paulo Afonso (MPE Garching), Adria Updike (Clemson University), Marco
Nardini, Robert Filgas, Abdullah Yoldas, and Jochen Greiner (MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 100316C (Swift trigger 416115; Stamatikos et
al. GCN 10491) 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 00:45 UT on March 17, 2010, 15.8 hours after the
GRB trigger, and are continuing. They were performed at an average seeing
of 1" and at an average airmass of 2.

We found a DSS uncataloged source at the edge of the 1.8 Swift-XRT error
circle reported by Evans et al. (GCN 10506) at

RA (J2000) = 02 h 09 m 09.11 s

DEC (J2000) = -67d 59' 26.8"

with an uncertainty of 0.5" in each coordinate.

Based on the first 31 min of total exposures in g'r'i'z', we estimate
preliminary magnitudes (all in AB system) of

g' = 23.7 +/- 0.1 mag,

r' = 24.4 +/- 0.1 mag,

i' > 23.6 mag,

z' > 23.9 mag.

Further observations are necessary to confirm variability.  If this is
indeed the afterglow of GRB 100316C, the colors indicate a redshift less
than 3.5.  Given magnitudes are calibrated against GROND zeropoints and
are not corrected for the expected Galactic foreground extinction
corresponding to a reddening of E_(B-V)=0.03 mag in the direction of the
burst (Schlegel et al. 1998).  JHK reduction is ongoing.


GRB_name: GRB100316D
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10517
SUBJECT: Tentative redshift of GRB100316D from X-ray data
DATE:    10/03/17 06:37:22 GMT
FROM:    Sergio Campana at INAF-OAB  <sergio.campana@brera.inaf.it>

S. Campana (INAF-OAB) reports on behalf of the Swift-XRT team:

Swift XRT observed GRB 100316D (Stamatikos et al. 2010, GCN10496)
in Windowed Timing (WT) mode in the 144-737 s time interval.
During this interval the light curve decays very slowly (decay
index alpha=-0.13, Starling et al. 2010, GCN 10505).
In addition, the 1.5-10 keV to 0.3-1.5 keV hardness ratio remains
constant (reduced chi2=0.91 with 97 degrees of freedom, dof).
Motivated by the high count rate (around 30 c s^-1, but far from
the pile up limit) and by the constant spectral shape we tried to
estimate the GRB redshift from the X-ray data.
We assume a Galactic column density of 7x10^20 cm^-2 (Kalberla et
al. 2005, A&A 440 775) and fit the WT spectrum taken from the
Leicester pages (http://www.swift.ac.uk/xrt_spectra/00416135/)
with an absorbed (phabs*zphabs) cutoff power law model (the cutoff
power law model provides much better results in terms of column
density evaluation with respect to a simple power law model when
small spectral variations are present). Given the high count rate
we selected single pixel events only.
The resulting fit is good (reduced chi2=1.2, 333 dof). The redshift
is constrained to lie within the 90% confidence level (delta
chi2=4.61) of 0.014<z<0.28 (with a best fit redshift of z=0.1 and
intrinsic column density of N_H(z)=7x10^21 cm^-2).
Filtering WT counts with grades 0-2 (standard WT grades) slightly
shifts the best fit range to larger redshifts (in the approximate
range 0.1-0.6).

The contour plot is available at
http://www.brera.inaf.it/utenti/campana/100316d.gif

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

[GCN OPS NOTE(18mar10):  Per author's request, the chi2=2.71 
was changed to chi2=4.61.]


GRB_name: GRB100316B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10518
SUBJECT: GRB 100316B: Swift-XRT refined analysis
DATE:    10/03/17 09:30:12 GMT
FROM:    Owen Littlejohns at U of Leicester  <oml2@star.le.ac.uk>

O. M. Littlejohns, P. A. Evans, K. L. Page (U. Leicester) and W. H.
Baumgartner (GSFC/UMBC) report on behalf of the Swift-XRT team:

We have analysed 2.9 ks of XRT data for GRB 100316B (Baumgartner et al.
GCN Circ. 10489), from 75 s to 40.1 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Beardmore et al. (GCN. Circ 10502).

The light curve can be modelled with a broken power-law decay with an
initial decay index of alpha=0.1 (+/-0.2), followed by a break at T~1100
s to a final decay of alpha=1.2 (+0.5, -0.1).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.35 (+0.24, -0.21). The
best-fitting absorption column is 4.1 (+2.7, -1.3) x 10^21 cm^-2, at a
redshift of 1.18 (Vergani et al. GCN Circ 10495), in addition to the
Galactic value of 9.9 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 3.4 x 10^-11 (5.8 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
1.2, the count rate at T+48 hours will be 6.6 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x
10^-14 (3.8 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00416103.

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


GRB_name: GRB100316D
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10519
SUBJECT: GRB 100316D: Swift XRT enhanced position and further refined analysis
DATE:    10/03/17 13:42:03 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1@star.le.ac.uk>

R.L.C. Starling, P.A. Evans (U. Leicester) and M. Stamatikos 
(OSU/NASA/GSFC) report on behalf of the Swift XRT team:

We have now analysed the first 3 orbits of Swift XRT data for GRB 100316D 
(trigger=416135, Stamatikos et al. GCN Circ. 10496),
comprising 8 s of Windowed Timing (WT) settling mode data, 593 s of WT
mode data and 3.7 ks of Photon Counting (PC) mode data. The early light
curve is flat and can be modelled with a power-law decay with a decay
index of alpha=0.13+/-0.03 as described in Starling et al. (GCN Circ.
10505). This now breaks at some time after T+750 s to a steeper decay of
alpha=2.0 +0.3/-0.1.

Using 1967 s of XRT Photon Counting mode data and 1 U-band 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 = 107.62763, -56.25547 which is equivalent to:

RA (J2000):  07h 10m 30.63s
Dec (J2000): -56d 15' 19.7"

with an uncertainty of 3.7 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, MNRAS, 397, 1177).
We note that this position is 1.5 arcsec from the optical/nIR candidate 
'Object A' reported in the VLT/X-Shooter and Gemini/GMOS observations by
Vergani et al. (GCN Circ. 10513) and GROND observations reported by Afonso
et al. (GCN Circ. 10514), and 2.9 arcsec from the candidate 'Object B'
reported in GCN Circ. 10513.

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


GRB_name: GRB100316D
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10520
SUBJECT: GRB 100316D: Swift/UVOT Observations
DATE:    10/03/17 16:54:15 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL), M. De Pasquale (MSSL-UCL) and M. Stamatikos  
(OSU/NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 100316D 148s after the BAT trigger (Stamatikos et al., GCN Circ.  
10496).
Coincident with the refined Swift XRT error circle (Starling et al.  
GCN Circ. 10519),
we detect the DSS galaxy, which hosts the sources A and B
(Vergani et al. GCN Circ. 10512, 10513), but we are unable to
resolve it. Our photometry, performed on 3ks of data
in the 7 UVOT filters, shows no change larger than 1 sigma in
the flux of this DSS galaxy.


GRB_name: GRB100316A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10521
SUBJECT: GRB 100316A: optical observations in CrAO
DATE:    10/03/18 01:23:18 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev (CrAO), A. Pozanenko (IKI)  report on behalf of larger GRB 
follow-up collaboration:

We observed the field of the Swift GRB 100316A (Baumgartner  et al. GCN 
10484) with Shajn telescope of CrAO starting (UT) March 16  19:15   under 
descending weather conditions and mean seeing of  2 arcsec. No object is 
detected in enhanced XRT error circle (Evans, GCN 10490).

The upper limit of point like object in a stacked image based on USNO-B1.0 
star 1618-0120609 (J2000) RA= 16:48:06.44 Dec= +71:50:15.2  (assuming 
R2=15.25)  is following:

T0+      Filter,   Exposure, mag.
(mid, d)              (s)

0.7061   R       8x60    > 21.6

The non-detection is strongly support the object of R~20.5 reported in GCN 
10487 (Gorosabel et al) is the optical afterglow of GRB100316A.


GRB_name: GRB100219A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10522
SUBJECT: GRB 100219A: optical upper limit 
DATE:    10/03/18 01:35:33 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (SAI MSU), E. Klunko (ISTP), and A. Pozanenko (IKI) report on 
behalf of larger GRB follow-up collaboration:

We observed the field of the Swift GRB 100219A (Rowlinson et al. GCN 10438) 
with AZT-33IK telescope of Sayan observatory (Mondy) starting on Feb.19 (UT) 
16:16:18, i.e. 1.0 hours after the burst. Observations  were carried out up 
to (UT) 16:59:26. We do not detect any objects in enhanced XRT error circle 
(Evans et al. GCN 10437). The upper limit (3 sigma) of stacked image of the 
first series is based on several USNO-B1.0 nearby stars:

T0+   Filter  Exposure  mag.
(mid, d)          (s)

0.0431   R    3x60      > 19.00 


GRB_name: GRB100316D
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10523
SUBJECT: GRB 100316D: Further Gemini observations
DATE:    10/03/18 02:55:05 GMT
FROM:    Andrew Levan at U.of Leicester  <A.J.Levan@warwick.ac.uk>

A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), P. D'Avanzo
(INAF-OAB), S.D. Vergani (GEPI-Obs. Paris), D. Malesani (DARK/NBI)
report for a larger collaboration.

"We re-observed the location of GRB 100316D (Stamatikos et al. GCN
10496; Starling et al. GCN 10519) using Gemini/GMOS in the r-band.
Observations began at 23:55 UT, approximately 36 hours after the
GRB, and 24 hours after our first epoch (Vergani et al. GCN 10513).
The seeing in the second epoch is slightly worse than the first
(0.9" versus 0.7") and so the resulting images are slightly shallower.
No obvious objects within the refined XRT error circle (Starling
et al. GCN 10519) show significant (>3 sigma) evidence for variation.
However, we do note the presence of a previously unreported
compact source that is within the X-ray error circle, but is close
to the nucleus of the galaxy, at

RA(J2000) = 07:10:30.54
Dec(J2000) = -56:15:20.0

This source is brighter than those previously discussed in GCN 10513
(R~20) but again, given the difficulty of performing accurate photometry
against a bright and varying background of the host, we can't as yet
make any firm statements about variability.

We note, it is of course possible that a brightening supernova
component and fading afterglow are conspiring to mask variability
between these two epochs, and further observations are planned.

We thank the staff of Gemini, in particular Rodrigo Carrasco for
their help in executing these observations."


GRB_name: GRB100316D
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10524
SUBJECT: GRB 100316D: Pre-burst emission measured by BAT
DATE:    10/03/18 21:13:59 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC/UMD), 
D. M. Palmer (LANL), M. Stamatikos (GSFC/OSU) 
(i.e. the Swift-BAT team):

Using the BAT hard X-ray survey data (Detector Plane Histogram data), we have 
processed the BAT survey data for pre- and post-trigger periods using the batsurvey 
script and have extracted the flux at the location of the GRB.  While Swift was pointing at 
GRB 100316C from T-2650 s to T-80 s, the GRB 100316D location was in the FOV of BAT.  
At 12:43, Swift slewed to a pre-planned target (1E 1048.1-5937), and triggered on GRB 100316D.  
After re-pointing to the location of GRB 100316D, Swift slewed away from GRB 100316D 
at T+750 s due to an observational constraint.  GRB 100316D came back into the FOV of BAT 
at T+5050 s (a pre-planned observation of 1E 1048.1-5937).  

The BAT light curve in the 14-195 keV band around the trigger time is available at:

-Light curve from T-6000 sec to T+6000 sec:
http://gcn.gsfc.nasa.gov/other/GRB100316D_bat_lc.gif

-Zoom-in light curve from T-2000 sec to T+1000 sec:
http://gcn.gsfc.nasa.gov/other/GRB100316D_bat_lc_zoomin.gif

The light curve produced by the BAT event-by-event data is overlaid with the survey light 
curve in the figure. There is a probable early low-level emission starting from T-1500 s. 
The emission then rises at T-500 s, peaks at T-100 s, and decays with an exponential 
decay constant of ~750 s.  The emission continues through the slew at T+750 s.  
The emission is no longer detected by BAT after T+5050 s.

As pointed out in Sakamoto et al. (GCN Circ. 10511), the BAT light curve profile of 
GRB 100316D is very similar to the GRB 060218-SN2006aj burst 
(Camapana, et al.; Nature, v224, p1008).  The BAT light curve of GRB 060218 shows 
a rise at T-300 s, a peak at T+450 s, and an exponential decay constant of ~500 s, 
with a duration of ~2000 sec.  GRB 100316D was detected in Swift-BAT from ~T-500 sec 
to at least ~T+800 sec, hence the lower limit on the duration of GRB 100316D is ~1300 sec.  
The fluence in the 15-150 keV band measured with the available 955 seconds of event data 
is 3.4 x 10^-6 erg/cm2.  This corresponds to an isotropic equivalent 
energy (Eiso) of 3.1x10^49 ergs in the 15.88 keV - 158.85 keV band at the GRB rest frame 
assuming a redshift z=0.059 of a potential source and a galaxy inside the XRT error 
circle (Vergani et al. GCN Circ. 10512, 10513).  This unusually long duration in 
concert with a soft spectrum and a low Eiso (Eiso of GRB 060218 was  
6.2x10^49 ergs) strengthens the similarity between GRBs 100316D and 060218.  Although 
the lack of a clear optical counterpart to GRB 100316D at this stage is distinctly 
different than GRB 060218, the prompt emission characteristics are very much like 
supernova-associated GRB 060218.  Hence, we suggest additional follow-up observations 
especially in the IR that may confirm the presence of a host supernova.  


GRB_name: GRB100316D
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10525
SUBJECT: GRB 100316D: Possible Supernova 
DATE:    10/03/19 12:32:17 GMT
FROM:    Andrew Levan at U.of Leicester  <A.J.Levan@warwick.ac.uk>

K. Wiersema (U. Leicester), P. D'Avanzo (INAF-OAB), A.J. Levan (U.
Warwick), N.R. Tanvir (U. Leicester), D. Malesani (DARK/NBI), S.
Covino (INAF-OAB) report for a larger collaboration:

"We obtained a third epoch of observations of the localization of
GRB 100316D (Stamatikos et al. GCN 10496; Starling et al. GCN
10519) using Gemini South and GMOS. Observations began at 23:48 UT
on March 18, and were obtained in the r-band under excellent
seeing (0.5"). Image subtraction reveals that the source previously
identified by Levan et al (GCN 10523), has brightened between the two
observations by ~0.3 magnitudes.  We suggest that this object
represents the rising supernova associated with GRB 100316D.

Images of the field, and the subtraction can be found at

http://www.star.le.ac.uk/~anl/100316D

Further observations are planned.

We thank the staff of Gemini for their help in executing these
observations"


GRB_name: GRB100319A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10526
SUBJECT: GRB 100319A: Swift detection of a burst; possible SGR
DATE:    10/03/19 19:05:59 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. M. Gelbord (PSU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), D. Grupe (PSU),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
J. P. Osborne (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU),
E. Troja (NASA/GSFC/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 18:34:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100319A (trigger=416485).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 278.442, -8.537 which is 
   RA(J2000)  =  18h 33m 46s
   Dec(J2000) = -08d 32' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single spike
structure with a duration of about 0.2 sec.  The peak count rate
was ~5000 counts/sec (15-350 keV), at ~0.0 sec after the trigger. 

The XRT began observing the field at 18:35:57.2 UT, 66.6 seconds after
the BAT trigger. In promptly downlinked data we detect a low
significance uncatalogued source at the following location (RA, Dec) = 
(278.43458, -8.51822), which is equivalent to:
   RA(J2000)  =  18h 33m 44.3s,
   Dec(J2000) = -08d 31m 05.6s,
with an uncertainty of 6.7 arcseconds (90% radius). This source lies 73 arcsecs
from the BAT position. We await further downlinked data to confirm if this source
is real. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 70 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 large, but uncertain extinction expected. 

Given the proximity of this burst to the Galactic Plane (0.01 degrees),
the shortness of the burst (16 ms trigger time) and soft emission
(with no visible emission seen above 100 keV), this burst may be
from an unknown Soft Gamma Repeater.  We note that this is 23 arcmin
from the center of the W41 supernova remnant in a region with several
known pulsars. 

Burst Advocate for this burst is J. M. Gelbord (jgelbord 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: GRB100219A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10527
SUBJECT: GRB 100219A: MASTER-Net  optical alert observations 
DATE:    10/03/19 19:50:44 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

V.Yurkov, Yu.Sergienko, D.Varda, A.Garusina 
Blagoveschensk Educational State University, Blagoveschensk


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

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


V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov Ural State University, Kourovka


K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok
Irkutsk State University


MASTER  robotic telescope (MASTER-Net: http://observ.pereplet.ru, 200
mm, FOV=8 square degrees (testing telescope) and  Very Wide Field Camera (D=50 
mm, 1000 square  degrees, 11 Mpx, 36" per pix, mounted on telescope)
located at Blagoveschensk   was responted to the  GRB 100219A (Swift Bat 
alert,
  Gelbord et al, GCN CIRC 10526)   64 sec after  Notice time and  78 s 
after 
the GRB time.

There is now OT on the first 20-s  exposition time image inside Swift XRT 
error box (Gelbord et al., GCN CIRC 10526) brighter 16.0.




The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100319A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10532
SUBJECT: GRB 100319A: correction to GCN 10527
DATE:    10/03/20 15:10:11 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

Vladimir Lipunov

I am sorry for mistakes in GCN 10527.
The Title: GRB 100319A: MASTER-Net  optical alert observations

Result:

There is no OT on the first 20-s  exposition time image inside 
Swift XRT error box (Gelbord et al., GCN CIRC 10526) brighter 16.0.





The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100316D
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10533
SUBJECT: GRB 100316D: ATCA radio observations
DATE:    10/03/20 15:52:22 GMT
FROM:    Alicia Soderberg at Harvard/CfA  <asoderbe@cfa.harvard.edu>

Mark Wieringa (CSIRO), Alicia Soderberg (Harvard/CfA), and Phil Edwards
(CSIRO) report:

"We observed the field of GRB 100316D (Stamatikos et al. GCN 10496) with
the Australia Telescope Compact Array beginning on Mar 18.35 for 3.5 hrs.
Data were collected at central frequencies of 5.4 and 9.0 GHz with 2 GHz
bandwidth each.  We do not detect any radio sources within the refined
XRT error circle (Starling et al. GCN 10519).  We place upper
limits of 104 microJy at 5.4 GHz and 165 microJy at 9.0 GHz (4 sigma).
At the redshift of the host galaxy (z=0.059; Vergani et al. GCN 10512),
these limits imply a radio spectral luminosity below 8e+27 erg/s/Hz
which is a factor of 2 to 10 lower than the radio afterglow luminosities
observed for nearby long-duration GRBs 980425 (Kulkarni et al. 1998),
031203 (Soderberg et al. 2004), and 060218 (Soderberg et al. 2006) on
comparable timescales.  Further observations are planned."


GRB_name: GRB100322A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10539
SUBJECT: GRB 100322A: Fermi GBM detection
DATE:    10/03/22 20:25:58 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

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

"At 01:05:09.64 UT on 22 March 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100322A (trigger 290912711 / 100322045).
The on-ground calculated location, using the GBM trigger data, is
RA=23.33, Dec=-10.22 (J2000 degrees, equivalent to 23h20m, -10d13'),
with an uncertainty of 1.20 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 96 degrees.

The GBM light curve consists of multiple peaks with a duration
(T90) of 37.0 +/- 0.3 s (50-300 keV).
The time-averaged spectrum from T0-1.0 s to T0+41.0 s is best fit by
a Band function with Epeak = 309 +/- 16 keV, alpha = -0.88 +/- 0.02,
and beta = -2.15 +/- 0.05 (Cstat 1095 for 602 d.o.f.).

The event fluence (10-1000 keV) in this time interval is
(6.13 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+1.1 s in the 10-1000 keV band
is 16.1 +/- 0.3 ph/s/cm^2.

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


GRB_name: GRB100316D
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10541
SUBJECT: GRB 100316D: Spectroscopic Discovery of a Supernova from Magellan
DATE:    10/03/22 22:19:26 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

R. Chornock, A. M. Soderberg, R. J. Foley, E. Berger, A. Frebel, P. Challis
(Harvard/CfA), J. D. Simon, and S. Sheppard (Carnegie) report:

We have been obtaining nightly spectra of GRB 100316D (Stamatikos et al., GCN
10496) with the MagE, LDSS3, and IMACS spectrographs on the twin 6.5-m Magellan
telescopes, starting on 2010 March 18.0 UT, approximately 1.5 days after the BAT
trigger.  All spectra included the variable point source found by Levan et al.
(GCN 10523) and Wiersema et al. (GCN 10525) within the slit aperture.

All spectra show superposed high-equivalent-width nebular emission lines at
z=0.059, in agreement with Vergani et al. (GCN 10512).  Our earliest spectra
show a very blue continuum with a few weak stellar features indicative of some
starlight from a young stellar population falling within our spectroscopic
aperture, but no other obvious features.  By the time of our most recent MagE
spectrum, from March 22.0 UT (T0+5.5 days), a few broad undulations in the
continuum have developed, although contamination from the galaxy light and
possibly an afterglow remains significant.  The strongest feature has a flux
peak near 7850 Angs (in the rest frame) and a minimum near 7280 Angs.  An
additional local minimum in the continuum is located near 5700 Angs with a broad
maximum located to the red of that.  The appearance of undulations in the
spectrum near the expected locations of supernova features from a comparison
with SN 1998bw at early times (while no such undulations appear in our earliest
spectra) leads us to conclude that we have spectroscopically determined that the
transient source which was detected photometrically (Wiersema et al., GCN 10525)
is a supernova.

A plot of an early and a recent spectrum compared to SN 1998bw can be found here:
http://www.cfa.harvard.edu/~eberger/grb100316d-mage.pdf


GRB_name: GRB100322B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10542
SUBJECT: GRB 100322B or possible Galactic transient detected in ground analysis of BAT data
DATE:    10/03/23 01:10:54 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
on behalf of the Swift team

At 7:06:18 on March 22, 2010, Swift-BAT detected a rate increase
(trigger #416771).  No source was detected onboard. A source was
detected in ground analysis at RA, Dec 76.489, +42.685, which is:

RA (J2000)   05h 05m 57.4s
DEC (J2000)  +42d 41'07"

with an estimated uncertainty of 4 arcmin (radius, 90% containment).
The source is 1 degree from the Galactic plane, and was 70% coded in
the BAT field of view.

The burst was short, consisting of a single peak with T90 of about
1.5 sec, and weak. The spectrum is best fit by a simple powerlaw with
a photon index of 1.6 +- 0.3.  The fluence from 15-150 keV was
5 +- 3 e-08 ergs/cm2.

While the burst duration and location near the galactic plane are
suggestive of a thermonuclear X-ray burst from a galactic neutron star
X-ray binary, the BAT spectrum argues against that interpretation.
There are about 360 square degrees within 1 degree of the galactic
plane, or ~1% of the entire sky.  Thus, it is certainly plausible for
this burst to be a cosmological GRB.

Because no source was detected onboard, there are no automated data
products.  A Swift TOO has been requested.


GRB_name: GRB100316D
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10543
SUBJECT: Emerging Supernova in the Afterglow of GRB 100316D
DATE:    10/03/24 13:37:52 GMT
FROM:    Filomena Bufano at INAF-Osb Astro di Padova  <filomena.bufano@oapd.inaf.it>

F. Bufano, S. Benetti, E. Cappellaro, INAF Osservatorio Astronomico di  
Padova (INAF-OAPd); S. Covino, INAF Osservatorio Astronomico di Brera  
(INAF-OABr); S. Vergani, P.Goldoni, GEPI (Observatoire de Paris) - APC  
(Universit Paris 7); M. Della Valle, INAF Osservatorio di  
Capodimonte; E. Pian, INAF Osservatorio Astronomico di Trieste; S.  
Campana, G.Tagliaferri, INAF-OABr; D.Malesani, J. Fynbo, Dark  
Cosmology Centre; M. Turatto, INAF Osservatorio Astronomico di  
Catania; F.Patat, European Southern Observatory (ESO) and P. Mazzali,  
INAF-OAPd  report on behalf of a larger colaboration that a high-dispersion
optical spectrum (range  350-900 nm, resolution 0.02 nm) of the afterglow
associated to GRB  100316D (cf. GCN 10496) was obtained with the VLT telescope  
(+XShooter) at ESO-Paranal on March 23.04 UT. The spectrum of  the  
source located at R.A.=07:10:31.8 and Decl.=-56:15:20.2, J2000 (as  
measured on the XShooter acquisition image) shows very broad bumps   
with peaks measured at about 430nm and 670nm reminiscent of an  
emerging broad line type Ic supernova (in agreement with Chornock et al,
GCN 10541). Indeed, above 600 nm the spectrum of this source
shows some similarities with that of SN 1998bw (Patat et al. 2001,
ApJ, 555, 900) taken 7 days after outburst.

There are however major differences  with the spectrum of this  
transient, showing a significant flux deficiency in the range  
450-550nm in comparison with SN 1998bw .

[GCN OPS NOTE(24mar10): Per author's request, the parenthetical
comment "(in agreement with Chornock et al, GCN 10541)"
was added.]


GRB_name: GRB100324A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10544
SUBJECT: GRB 100324A found in ground analysis of BAT data
DATE:    10/03/24 17:57:55 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

J. R. Cummings (GSFC/UMBC) and D. M. Palmer (LANL)
on behalf of the Swift team

At 00:21:27 on March 24, 2010, Swift-BAT detected a rate increase.  The
source was found onboard, but not at sufficient significance to trigger
an automated GRB followup response.  A significant source was found in
ground analysis at RA, Dec 98.612, -9.735, which is:

RA (J2000)    06h 34m 26.8s
Dec (J2000)   -9d 44' 6.4"

with an estimated uncertainty of 2.5 arcmin (radius, 90% containment).

The burst had multiple peaks with a T90 of about 6 seconds.

The spectrum of the burst is best fit with a simple powerlaw with a
rather soft index of 2.4 +- 0.3.  The fluence in the range 15-150 keV
was 7 +- 3 x 10^-8 erg/cm^2 (68% confidence).  The 1-second peak flux
from T-0.3 sec was 0.3 +- 0.1 photons/cm^2.

Because the burst was not triggered onboard, there are no automated
data products.  A Swift TOO has been requested.


GRB_name: GRB100324A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10545
SUBJECT: GRB 100324A: GROND observations
DATE:    10/03/26 13:59:40 GMT
FROM:    Felipe Olivares Estay at MPE  <felipe@mpe.mpg.de>

A. Updike (Clemson University), M. Nardini, A. Rau, F. Olivares, and
J.Greiner (all MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 100324A (ground analysis of Swift/BAT
data, Cummings et al., GCN #10544) simultaneously in g'r'i'z'JHK with
GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO
telescope at La Silla Observatory (Chile). Observations started on 24
March 2010 at 23:41 UT, 23.3 hours after the GRB. The field was
observed during a second epoch, starting at 00:10 UT on 26 March 2010,
47.9 hours after the burst.

Our i'-band and H-band observations cover 95% and 100% of the 2.5' BAT
error circle, respectively. Image subtraction between the two
observing epochs does not reveal any variable source. The first image,
consisting of 24.8 min exposure in g'r'i'z' and 20 min in JHK, yields
the following 3-sigma upper limits (both AB magnitudes):

i' > 23.6 mag
H > 21.6 mag

which were obtained using the GROND zero points and 2MASS field stars
as reference. The given magnitudes are not corrected for the
significant Galactic extinction corresponding to a reddening of E(B-V)
= 0.71 mag (Schlegel et al. 1998).


GRB_name: GRB100325A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10546
SUBJECT: GRB 100325A: Fermi GBM detection
DATE:    10/03/26 14:26:50 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

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

"At 06:36:08.02 UT on 25 March 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100325A (trigger 291191770/100325275).

The on-ground calculated location, using the GBM trigger 
data, is RA = 332.3, DEC = -28.6 (J2000 degrees, 
equivalent to 22h 09m, -28d 36'), with an uncertainty 
of 1.5 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 9 degrees.

The GBM light curve consists of a single structured pulse with a 
duration (T90) of 8.3 +/- 1.9 s (8-1000 keV).

The time-averaged spectrum from T0-1.664 s to T0+7.552 s is 
best fit by a power law function with an exponential
high energy cutoff. The power law index is -0.45(+0.12/-0.11) and
the cutoff energy, parameterized as Epeak, is 159.3 (+12.7/-10.8) keV
(CSTAT 502 for 482 d.o.f).

The event fluence (8-1000 keV) in this time interval is 
(1.99 +/- 0.04)E-06 erg/cm^2. The 1.024-sec peak photon flux measured 
starting from T0+0.512 s in the 8-1000 keV band 
is 5.0 +/- 0.2 ph/s/cm^2.

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


GRB_name: GRB100316D
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10547
SUBJECT: GROND observations of GRB100316D/SN2010bh
DATE:    10/03/26 22:58:43 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne  Rau, Marco Nardini  (both MPE  Garching), Adria  Updike (Clemson
University), Robert  Filgas, Jochen Greiner, Thomas  Kruehler (all MPE
Garching), and Sylvio  Klose (TLS Tautenburg) report on  behalf of the
GROND team:

We  report on  additional observations  of  the field  of GRB  100316D
(Swift trigger 416135; Stamatikos et al., GCN 10496) simultaneously in
g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at
the  2.2  m  MPI/ESO   telescope  at  La  Silla  Observatory  (Chile).
Observations started  on 17 March 2010  at 00:27 UT,  11.7 hours after
the burst (Afonso et al., GCN Circular #10514). The field was observed
during additional 16 epochs and observations are continuing.

Image subtraction revealed the supernova SN2010bh reported by Wiersema
et al.  (GCN Circular #10525),  Chornock et al. (GCN Circular #10541),
and Bufano  et al.   (GCN Circular #10543)  to emerge approx.   5 days
post-burst and  to reach an AB  magnitude of r  ~ 18.8 +/- 0.2  at 7.5
days post-burst.

The observed light  curve evolution of SN2010bh is  similar to that of
SN1998bw  (Galama  et  al.    1998),  the  supernova  associated  with
GRB980425, shifted to the  redshift of GRB100316D (z=0.059; Vergani et
al., GCN  Circular #10512).  The  optical luminosity is  comparable to
SN1998bw,  except in  the  g-band,  where the  flux  is suppressed  by
approx.   30%.   This  likely  corresponds  to  the  significant  flux
deficiency in the range 450-550nm reported from the X-Shooter spectrum
(Bufano et al., GCN Circular #10543).


GRB_name: GRB100325A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10548
SUBJECT: GRB 100325A: Fermi LAT detection
DATE:    10/03/27 22:09:54 GMT
FROM:    Francesco de Palma at U of INFN Bari  <francesco.depalma@ba.infn.it>

Francesco de Palma (INFN and Universit di Bari),Takeshi Uehara 
(Hiroshima University), Johan Bregeon (INFN Pisa), Veronique Pelassa
(CNRS/IN2P3/LPTA), Jim Chiang (SLAC), Fred Piron (LPTA), Nicola Omodei
(Stanford) report on behalf of the Fermi LAT collaboration:

At 06:36:08.02 UT on 25 March 2010, the Fermi Large Area Telescope (LAT)
detected gamma rays from the GRB 100325A, which was triggered and 
located by the Fermi Gamma-ray Burst Monitor (GBM)
(trigger 291191770/100325.275,GCN10546). The angle of the GBM position
position with respect to the LAT boresight was ~9.2 degrees at the time
of the LAT detection, close to the center of the LAT field of view.

The data from the Fermi LAT shows a weak increase in the event rate
that is spatially and temporally correlated with the GBM emission.
It is a relatively weak detection (~>4 sigma) with 4 photons above
100 MeV within 9 seconds after the GBM trigger.
The highest energy photon has an energy just above 800 MeV.

The best LAT on-ground localization is found to be (RA, Dec = 330.24,
-26.47) (J2000) with a 90% containment radius of 0.9 deg 
(statistical; 68% containment radius: 0.6 deg) which is consistent with 
the GBM localization. The observed flux (100 MeV-300 GeV) from this 
location is 1.18 +/- 0.76 e-04 (ph/cm^2/s).

Further analysis is ongoing.

The point of contact for this burst is Francesco de Palma
(francesco.depalma@ba.infn.it)

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: GRB100322A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10550
SUBJECT: GRB 100322A: Suzaku WAM observation of the prompt emission
DATE:    10/03/30 00:43:45 GMT
FROM:    Satoshi Sugita at Aoyama Gakuin U.  <sugita@phys.aoyama.ac.jp>

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

The bright long GRB 100322A  (Fermi/GBM trigger #290912711
; van der Host et al., GCN 10539)
triggered the Suzaku Wide-band All-sky Monitor (WAM)
which covers an  energy range of 50 keV - 5 MeV
at 2010-03-22 01:05:09.65 UT (=T0).

The observed light curve shows a multi-peaked structure
lasting from T0 to T0+50s and a weak post cursor
seen at T0+70s with T90 of about 37 seconds.
The fluence in 100 - 1000 keV was 5.00 (-0.17, +0.09)x10^-5 erg/cm^2.
The 1-s peak flux measured from T0+33s was
8.04 (-0.39, +0.26) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0 to T0+42s is well fitted by a power-law with exponential cutoff model:
dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha       1.42 (-0.15, +0.13), and
Epeak       601 (-57, +70) keV (chi^2/d.o.f. = 26.2/24).

Due to the brightness of this burst, a 2% systematic error
was added for each energy channel.
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: GRB100322A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10553
SUBJECT: Konus-Wind observation of GRB 100322A
DATE:    10/03/30 13:00:13 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long intense GRB 100322A (Fermi/GBM trigger #290912711,
van der Host et al., GCN 10539) triggered Konus-Wind
at T0=03905.772s UT (01:05:05.772)

The burst light curve shows a complex structure containing
two main pulses with a total duration of ~50 s.
Additionally, a much weaker pulse was observed around T0+75s.

The first of the two main pulses has a distinctly softer spectrum
than the second one. No evident spectral evolution was detected
within the pulses.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB100322_T03905/

As observed by Konus-Wind the burst
had a fluence of 7.3(+/-0.5)x10-5 erg/cm2,
and a 256-ms peak flux measured from T0+31.744s
of 6.5(+/-0.4)x10-6 erg/cm2/s
(both in the 20 keV - 5 MeV energy range).

The spectrum of the first, softer pulse
(measured from T0 to T0+16.384 s) is well fitted
in the 20 keV - 5 MeV range by a power law
with exponential cutoff model, for which
alpha = -0.86(+/-0.15),
and Ep = 150(-10, +12) keV (chi2 = 72/74 dof).

The spectrum of the second, harder part of the burst
(from T0+16.384 to T0+45.568 s) is also well fitted
in the 20 keV - 5 MeV range by a power law
with exponential cutoff model, for which
alpha = -0.99(+/-0.06),
and Ep = 610(-62, +75) keV (chi2 = 77/74 dof).

The spectrum at the maximum count rate
(measured from T0+31.744 to T0+37.376 s) is well fitted
in the 20 keV - 5 MeV range by a power law
with exponential cutoff model, for which
alpha = -0.92(+/-0.07),
and Ep = 707(-70, +82) keV (chi2 = 72/74 dof).

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


GRB_name: GRB100324B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10554
SUBJECT: IPN triangulation of GRB100324B
DATE:    10/03/31 00:01:13 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@ssl.berkeley.edu>

K. Hurley, on behalf of the IPN team,

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, D. Frederiks, and
T. Cline, on behalf of the Konus-Wind team,

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

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

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

This bright, long GRB was detected by Fermi (GBM), Suzaku (WAM),
Konus-Wind, Mars Odyssey (HEND), and MESSENGER (GRNS) AT 04:07:36 UT on
March 24, 2010.  We have triangulated it to a preliminary, 38 square
arcminute (3 sigma) error box whose coordinates are:


         RA(2000)       Dec(2000)
Center   39.672         -19.287 

Corners  39.713         -19.311
         39.717         -19.449
         39.628         -19.123
         39.632         -19.262

This error box may be improved.  Details of this burst will be presented
in forthcoming GCN Circulars.


GRB_name: GRB100331A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10555
SUBJECT: GRB 100331A: A long GRB detected by INTEGRAL
DATE:    10/03/31 06:29:12 GMT
FROM:    Sandro Mereghetti at IASF/CNR  <sandro@iasf-milano.inaf.it>

S.Mereghetti, A. Paizis, (IASF- Milano), D.Gotz (CES-Saclay), E.  Bozzo, 
C. Ferrigno, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on 
behalf of the IBAS Localization Team report:

a long GRB has been detected by IBAS in IBIS/ISGRI data at 00:30:30 UT of 
March 31. The refined coordinates (J200) are

RA: 261.0831 [degrees] 
DEC: -58.943 [degrees]

with an uncertainty of 2.5 arcmin

The lightcurve shows a single peak lastiing about 15 s. A preliminary 
analysis gives a 20-200 keV fluence of 4 10e-7 erg/cm2 and a peak flux of 
0.5 ph/cm2/s (1 sec bin).

A plot of the light curve will be posted at

http://ibas.iasf-milano.inaf.it/IBAS_Results.html

This message can be cited.

[GCN OPS NOTE(31mar10): Per author's request, the typo "January 31"
in the first sentence was changed to "March 31".]


GRB_name: GRB100324B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10556
SUBJECT: Konus-Wind observation of GRB 100324B
DATE:    10/03/31 08:10:47 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long bright GRB 100324B (localized by IPN;
Hurley et al., GCN 10554) triggered Konus-Wind
at T0=14852.507s UT (04:07:32.507)

The burst light curve shows a complex structure
with a total duration of ~15 s. A hard to soft
spectral evolution is apparent in the course of the burst.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB100324_T14852/

As observed by Konus-Wind the burst
had a fluence of 4.6(+/-0.2)x10-5 erg/cm2,
and a 256-ms peak flux measured from T0+4.864s
of 8.8(+/-0.6)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+13.824 s) is well fitted
in the 20 keV - 2 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.51 (-/+0.09),
the high energy photon index beta = -2.95(<-2.6),
the peak energy Ep = 397(-30, +41)keV (chi2 = 59/57 dof).

The spectrum at the maximum count rate
(measured from T0+3.840 to T0+5.632 s) can be fitted
in the 20 keV - 2 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.42 (-/+0.16),
the high energy photon index beta = -2.6(-0.85,+0.25),
the peak energy Ep = 283(-30, +44)keV (chi2 = 71/57 dof).

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


GRB_name: GRB100331A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10557
SUBJECT: GRB 100331A: BOOTES-3 observations
DATE:    10/03/31 10:13:18 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (INAF-OAB),  A.J. Castro-Tirado, J. Gorosabel,
M. Jelinek (IAA-CSIC), P. Kubanek (IPL UV, IAA-CSIC),
R. Cunniffe, S. Guziy (IAA-CSIC), P. Yock  (Auckland Univ.), W.H.
Allen (Vintage  Lane Obs.), I. Bond (Massey Univ.), G. Christie
(Stardome Obs.), report on behalf of a larger collaboration, report:

We have observed the field of the INTEGRAL GRB 100331A
(Mereghetti et al. GCN 10555) using the 0.6 Yock-Allen robotic
telescope (BOOTES-3) located in Blenheim, New Zealand starting
at 07:12 UT (6.7 hours after the burst). In a 35x60s combined exposure
with clear filter, obtained under non optimal conditions, we do not
detect any new source within the full INTEGRAL error circle down to a
3-sigma limiting magnitude of R~17.8. Further analysis is ongoing.


GRB_name: GRB100331A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10558
SUBJECT: INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
DATE:    10/03/31 15:23:42 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

Adria Updike (Clemson University), Arne Rau, Felipe Olivares, and
Jochen Greiner (all MPE Garching) report on behalf of the GROND team:
  
We observed the field of GRB 100331A (INTEGRAL trigger 5994; S.
Mereghetti et al., GCN 10555) 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 03:55 UT on March 31st 2010, 3.42 hours after the
Swift trigger, and a second epoch was obtained starting at 09:37 UT. They
were performed at an average seeing of 1" and at airmasses of 2.4
and 1.15, respectively.        
  
We found a single variable point source within the 2.5' INTEGRAL error
circle reported by S. Mereghetti et al. at
  
RA  (J2000) =  17h 24m 18.61s
DEC (J2000) = -58d 56' 52.0" 
  
with an uncertainty of 0.5" in each coordinate. From the last epoch we
estimate preliminary magnitudes (all in AB system) of  the
  
g' = 16.7 +/- 0.1 mag,
r' = 16.3 +/- 0.1 mag, 
i' = 16.4 +/- 0.1 mag,
z' = 16.2 +/- 0.1 mag, 
J  = 16.3 +/- 0.1 mag,
H  = 16.5 +/- 0.1 mag
K  = 16.9 +/- 0.1 mag,

calibrated against GROND zeropoints, and not corrected for the expected 
galactic foreground extinction of E(B-V)=0.12 mag (Schlegel et al. 1998).

During the observations the source varied by 0.4 mag in the g' and only 
0.2 mag in J, with no obvious fading over the 5.5 hrs. Both, the SED shape 
and the color evolution are different from any GRB afterglow observed so far 
with GROND. Though the object lies within 20 arcsec of the center of the 
INTEGRAL error circle, and the chance coincidence with a variable object 
within the 2.5 arcmin error circle is about 10^-4, the relation of this 
variable to the INTEGRAL trigger is likely, but cannot be proven at this 
stage.

We note the presence of an object in both, USNO and 2MASS at the location 
of the variable source. The 2MASS magnitudes are similar to our last epoch,
bright state measurement, indicating that this object is a long-term variable.
This excludes that this object is an host galaxy unresolved in our images.
Spectroscopic observations are encouraged to establish the nature of
this source.


GRB_name: GRB100331A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10559
SUBJECT: INTEGRAL trigger 5994 (GRB100331A): Swift/XRT observations
DATE:    10/03/31 23:33:37 GMT
FROM:    Valerio D'Elia at INAF-OAR  <delia@oa-roma.inaf.it>

G. Stratta, V. D'Elia, M. Perri (ASDC) report on behalf of the Swift Team:

Swift began a target of opportunity observation of the INTEGRAL detected 
GRB 100331A (Mereghetti et al., GCN #10555), at 14:29UT on March 31st, 2010,
approximately 14 hours after the INTEGRAL detection. In 1890 s of Photon
Counting mode data, no X-ray source is detected inside the INTEGRAL error cirlce. 

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

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GRB_name: GRB100331B
Detection_method: superAGILE
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10560
SUBJECT: GRB 100331B: SuperAGILE Localization of a Long GRB
DATE:    10/04/01 09:04:47 GMT
FROM:    Marco Feroci at IASF/INAF  <sa.grb@iasf-roma.inaf.it>

E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci, F. Lazzarotto,
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, F. D'Ammando (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, 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, E. Striani, (INFN Roma-2), M. Prest, E. Vallazza  
(Universita' dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), and   
P. Giommi, C. Pittori,
F. Lucarelli, P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI),
on behalf of the AGILE Team, report:

"SuperAGILE detected a gamma ray burst on 31 March 2010, at 21:08:38 UT.
The event had a duration of about 30 s in the 20-60 keV energy range,
with a multi-peak structure. AGILE is currently operating in a  
spinning mode and the reported duration may be a lower limit to the  
GRB duration.

The burst position was reconstructed as (RA, Dec)
(302.987, -11.067) deg, which is:

RA(J2000)  = 20h 11m 56.95s
Dec(J2000) = -11d 04' 02.04"

with an uncertainty of 6' radius to account for possible systematics  
error due to the spinning mode.

The GRB is not detected by the AGILE/MCAL (above 350 keV) nor AGILE/GRID
(30 MeV - 30 GeV)."

This message may be cited.


GRB_name: GRB100331B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10562
SUBJECT: GRB 100331B: Swift/XRT possible afterglow candidate
DATE:    10/04/02 00:38:12 GMT
FROM:    Valerio D'Elia at ASDC  <delia@asdc.asi.it>

V. D'Elia and G. Stratta (ASDC) report on behalf of the Swift Team:

Swift began a target of opportunity observation of the SuperAGILE detected
GRB 100331B (Del Monte et al., GCN #10560), at 14:38UT on April 1st, 2010,
about 17.5 hours after the SuperAgile detection.

We have analysed 2.1 ks of XRT data, from 63152 s to 69.7 ks after  
the    BAT trigger.
The data are entirely in Photon Counting (PC) mode. Using 1839 s of PC
mode data and 2 UVOT images, we find an enhanced XRT position (using
the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 303.02160, -11.10810 which is equivalent to:

RA (J2000): 20 12 5.18
Dec(J2000): -11 06 29.0

with an uncertainty of 2.0 arcsec (radius, 90% confidence). This
position lies 3.2 arcmins from the SuperAGILE reported position. We
currently cannot confirm if this source is fading.

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

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GRB_name: GRB100331B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10563
SUBJECT: GRB 100331B: Swift/UVOT Upper Limits
DATE:    10/04/02 02:12:21 GMT
FROM:    Michele Stark at PSU/Swift  <stark@astro.psu.edu>

M. A. Stark (PSU), G. Stratta (ASDC), E. A. Hoversten (PSU), and
M. H. Siegel (PSU) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of the
SuperAGILE detected GRB 100331B about 17.5 hours after the SuperAGILE
detection (Del Monte et al., GCN #10560).  No optical afterglow
consistent with the XRT enhanced position reported by D'Elia & Stratta
(GCN #10562) is detected in the initial UVOT exposure.  Observations
were conducted using only the UVOT white filter, with a preliminary
3-sigma upper limit using the UVOT photometric system (Poole et
al. 2008, MNRAS, 383, 627) for the initial exposure of:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
---------------------------------------------------------------
white            63371        64517          650         >21.21

The value quoted above is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.12 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB100324B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10564
SUBJECT: GRB 100324B: Suzaku WAM observation of the prompt emission
DATE:    10/04/02 03:41:31 GMT
FROM:    Masanori Ohno at ISAS/JAXA  <ohno@astro.isas.jaxa.jp>

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


The bright IPN localized GRB 100324B (GCN 10554 ; Hurley et al.)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an 
 energy range of 50 keV - 5 MeV at 04:07:36.130 UT (=T0). 
The observed light curve shows a multi-peaked structure starting at T0s, ending 
 at T0+10s, with a duration (T90) of about 9.7 seconds. 
The fluence in 100 - 1000 keV was 3.20 (-0.07, 0.05) x10^-05 erg/cm^2. 
The 1-s peak flux measured from T0+2s was 15.7 +/- 0.3 photons/cm^2/s in the same 
 energy range.

Preliminary result shows that the time-averaged spectrum from 
T0s to T0+10s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -0.91 (-0.14, 0.16),
the high-energy photon index beta: -3.05 (-0.53, 0.26),
and the peak energy Epeak: 472 (-25, 27) keV (chi^2/d.o.f = 61.2/50).

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: GRB100316A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10565
SUBJECT: GRB 100316A: R-band limit
DATE:    10/04/02 12:51:11 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

Jang, M., Im, M. (SNU), and Y. Urata (NCU) report on behalf of
the EAFON collaboration:

  We observed GRB100316A in R-band starting at 2010 March16, 08:09:17UT,
or 20.78 ks after the BAT triggered (Baumgartner et al, GCN 10484),
using the 1.0m telescope at Mt.Lemmon in Arizona, U.S. operated
by Korea Astronomy Space Science Institute.

  No afterglow candidate was detected from a stacked image of eight 300s-frames.
within the error circle of the enhanced XRT position (Evans et al.,GCN 10490).
We estimate the 3-sigma limiting magnitude of the afterglow to be 
R ~ 22.0 +/- 0.2 at the midpoint time of the stacked image (~T0+21.98 ks)
by calibrating it against sixteen USNO-B1 stars near the GRB, using their
R2 magnitudes without correcting for the Galactic extinction.

  Our limit indicates fading of the optical afterglow candidate reported by
Gorosabel et al. (GCN 10488) shortly after.

  We thank the LOAO operator, I. Baek for her help with the observation


GRB_name: GRB100331B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10566
SUBJECT: GRB 100331B: BOOTES-3 observations
DATE:    10/04/02 15:09:25 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (INAF-OAB),  A.J. Castro-Tirado, J. Gorosabel,
M. Jelinek (IAA-CSIC), P. Kubanek (IPL UV, IAA-CSIC),
R. Cunniffe, S. Guziy (IAA-CSIC), P. Yock  (Auckland Univ.),
W.H. Allen (Vintage  Lane Obs.), I. Bond (Massey Univ.), G. Christie
(Stardome Obs.), report on behalf of a larger collaboration, report:

We have observed the field of the AGILE GRB 100331B
(Del Monte et al. GCN 10560) using the 0.6m Yock-Allen robotic
telescope (BOOTES-3) located in Blenheim, New Zealand.
A combined 36x60s unfiltered exposure with mean epoch 1st
April 2010 at 16:30 UT (19.2 hours after the burst) obtained through
cirrus does not show any source within the Swift/XRT error circle
(D'Elia et al. GCN 10562) down to a 3-sigma limiting magnitude
of R~18.5 using USNO-B1.0 as photometric reference.


GRB_name: GRB100401A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10567
SUBJECT: GRB 100401A Burst, possibly short, detected in ground analysis of BAT data
DATE:    10/04/02 19:57:49 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), N. Gehrels (NASA/GSFC), F. E. Marshall (NASA/GSFC)
on behalf of the Swift team


At 2010-04-01T07:07:31.9 BAT detected a rate increase (trigger# 417974).
The source was found with insufficient significance onboard to trigger
an automated burst response.  A significant source was found in ground
analysis at RA, Dec 290.813, -8.257, which is:

RA (J2000)   19h 23m 15.5s
Dec (J2000) -08d 15' 25"

with an estimated uncertainty of 2 arcmin radius (90% containment). The
source was 10% coded in the BAT field of view.

As seen in BAT, the burst had a single square-shaped pulse of about
2 seconds duration.

The spectrum from 15 to 150 keV is best fit by a simple power law function
with a photon index of 1.7 +- 0.2.  We note that this is softer than is
typical for "short, hard" GRBs.  The fluence was (3.6 +- 1.2) erg/cm2.  The
1-second peak flux was 2.4 photons/cm2.

Since this burst was not detected with sufficient significance onboard,
there are no automated data products.  A Swift TOO is in progress.


GRB_name: GRB100401A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10568
SUBJECT: GRB 100401A: Fermi GBM detection
DATE:    10/04/02 22:59:08 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein@msfc.nasa.gov>

A. Goldstein (UAH) and D. Gruber (MPE) 
report on behalf of the Fermi GBM Team: 

"At 07:07:32.24 UT on 1 April 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100401A (trigger 291798454 / 100401297)
which was also detected by the Swift-BAT (J.R. Cummings et al. 2010,
GCN 10567).  The GBM on-ground location is consistent with the 
Swift-BAT position. The angle from the Fermi LAT boresight is 45 degrees.

The GBM light curve consists of an initial bright pulse at trigger time
lasting ~4 s followed by a second, much softer pulse of ~30 s in duration,
approximately 65 s after trigger time. The total duration (T90) is 
estimated to be about 100 s (8-1000 keV). The time-averaged spectrum of 
the first pulse from T0-1.9 s to T0+3.2 s is best fit by a power law 
function with an exponential high energy cutoff.  The power law index is 
-1.49 +/- 0.17 and the cutoff energy, parameterized as Epeak, is 
144.90 +/- 62.20 keV (chi squared 439 for 483 d.o.f.). The first 
pulse is equally well fit by a simple power law with index 
-1.77 +/- 0.06 (chi squared 444 for 484 d.o.f.).  The 
time-averaged spectrum of the second pulse from T0+74.9 s to 
T0+98.4 s is well fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.52 +/- 0.39 and
the cutoff energy, parameterized as Epeak, is 29.34 +/- 8.96 keV
(chi squared 511 for 483 d.o.f.).  The second pulse is equally well
fit by a simple power law with index -2.16 +/- 0.11 (chi squared 
514 for 484 d.o.f.).

The event fluence (8-1000 keV) over the entire emission is 
(2.39 +/- 0.05)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0-1.4 s in the 8-1000 keV band 
is 3.61 +/- 0.16 ph/s/cm^2.

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


GRB_name: GRB100401A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10569
SUBJECT: Swift/BAT trigger 417974 (GRB100401A): Swift/XRT observations
DATE:    10/04/03 00:55:02 GMT
FROM:    Valerio D'Elia at ASDC  <delia@asdc.asi.it>

G. Stratta and V. D'Elia (ASDC) report on behalf of the Swift Team:

Swift began a target of opportunity observation of
GRB 100401A detected on ground (Cummings et al., GCN #10567)
and by the Fermi/GBM (Goldstein and Gruber, GCN #10568), at
19:33:04 UT on April 2nd, 2010, approximately 36.4 hours after the
Swift/BAT trigger. In about 2 ks of Photon Counting
mode data, no X-ray source is detected inside the BAT
error circle.

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

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GRB_name: GRB100401A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10570
SUBJECT: GRB 100401A:  Swift/UVOT Upper Limit
DATE:    10/04/03 04:46:02 GMT
FROM:    Margaret Chester at PSU  <chester@astro.psu.edu>

M.M. Chester (PSU) and G. Stratta (ASDC) report on behalf of the
Swift/UVOT team:

Swift began a Target of Opportunity observation of GRB 100401A,
detected by Swift/BAT (Cummings et al., GCN Circ. 10567) and by
Fermi/GBM (Goldstein and Gruber, GCN Circ. 10568), on April 2nd,
2010 at 19:33:04 UT, approximately 36 hours after the Swift/BAT
trigger.

No optical afterglow consistent with the BAT position is detected
in the UVOT exposure. The 3-sigma upper limit using the UVOT
photometric system (Poole et al. 2008, MNRAS, 383, 627) is:

Filter     T_start(s)   T_stop(s)      Exp(s)      3-sig UL (mag)

u          131128       133123         1963         >20.8

The value quoted above is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.29 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB100331B
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10572
SUBJECT: GRB 100331B: GROND Upper limits
DATE:    10/04/03 10:40:30 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

Adria Updike (Clemson University), Paulo Afonso, and Jochen Greiner (both
MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 100331B (SuperAGILE; Del Monte et al., GCN
#10560) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory 
(Chile). Observations started at 09:31 UT on April 1, 2010, 12.37 hours after 
the GRB trigger, and a second epoch was taken beginning at 08:50 UT on April
2. They were performed at an average seeing of 1.0" and at an average
airmass of 1.3.

We do not detect a source within the Swift-XRT error circle reported by
D'Elia et al. (GCN #10562).  Upper limits from the first epoch are limited
to the NIR bands; the GROND observation was executed prior to the Swift/XRT
observation, and the XRT position turned out to be outside the FOV of our
optical channels.

On April 1, our upper limits were:
J > 21.5,
H > 21.0,
K > 20.2
from a total of 960 seconds of exposure time.

On April 2, our upper limits were:
g' > 24.6,
r' > 25.1,
i' > 24.5,
z' > 24.4,
J  > 22.6,
H  > 22.1 and
K  > 20.9
from a total of 2952 seconds of exposure in the optical bands and 2320
seconds in the NIR.

These 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)= 0.12 in the
direction of the burst (Schlegel et al. 1998).


GRB_name: GRB100403A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10576
SUBJECT: INTEGRAL  Alert n. 5995: MASTER-Net  optical  observations 
DATE:    10/04/04 15:26:04 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

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


V.Yurkov, Yu.Sergienko, D.Varda, A.Garusina Blagoveschensk Educational State 
University, Blagoveschensk



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


V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov
Ural State University, Kourovka


K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok
Irkutsk State University


Two MASTER  robotic telescopes (MASTER-Net: http://observ.pereplet.ru)
located at Vostryakovo (Moscow) and Tunka-Baykal   was responted to the GRB 
100403A (Integral alert 5995)   16 sec after  Notice time and  35 s after the 
GRB time and 36 sec after  Notice time and  55 s
after the  GRB time.

Baykal weather is bad. Moscow weather is good.

The Moscow result is:

  T-T_grb           Exp    m_lim          Band

  36                30s     17         Unfiltered

The optical star HDE 245770 (~9m V) not saturated (companion of the X-ray 
pulsar A0535+26).


It is interesting that both last INTEGRAL and Swift BAT alerts (GCN 
10561, GCN 10573) are the result activity of the X-ray Pulsars with Be 
stars ( A0535+26 and LS V +44 17).
By the way the X-ray pulasar A0535+26 is the NS with high magnetic field
~ 10^14 Gs (see very old paper Lipunov 1982, Soviet Astronomy, vol. 
26,  537  or monograph: V.M. Lipunov, "Astrophysics of Neutron Stars", 
Springer-Verlag, Berlin, New-York,  1992).


The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100401A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10577
SUBJECT: GRB100401A: GROND Upper Limits
DATE:    10/04/04 23:41:40 GMT
FROM:    Paulo M. J. Afonso at MPE  <pafonso@mpe.mpg.de>

SUBJECT: GRB100401A, GROND Upper Limits

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

We observed the field of GRB 100401A (Cummings et al., GCN #10567,
Goldstein and Gruber, #GCN 10568)  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 on 2010, April 3, at 09:21 UT, 2.09 days after the
burst, and consisted of 20 min in JHK and 24.6 min in g'r'i'z'. A second
epoch was obtained on 2010, April 4, at 09:09 UT, 2.99 days after the burst.

Image subtraction of the two epochs does not reveal a variable source,
down to the following 1st epoch limiting magnitudes (all in AB system):

g' > 23.7
r' > 23.9
i' > 23.4
z' > 23.4
J  > 21.8
H  > 21.4
K  > 20.3

These magnitudes were obtained using 2MASS field stars and GROND
zero-points as reference, and are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.29 mag in the direction of
the burst (Schlegel et al. 1998).


GRB_name: GRB100413A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10581
SUBJECT: GRB 100413A: Swift detection of a burst
DATE:    10/04/13 17:51:18 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. T. Holland (CRESST/USRA/GSFC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), S. Campana (INAF-OAB),
M. M. Chester (PSU), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), E. A. Hoversten (PSU),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
N. P. M. Kuin (UCL-MSSL), V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), A. Rowlinson (U Leicester),
B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU),
R. L. C. Starling (U Leicester), M. C. Stroh (PSU),
G. Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/ORAU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 17:33:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100413A (trigger=419404).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 266.217, +15.837 which is 
   RA(J2000)  =  17h 44m 52s
   Dec(J2000) = +15d 50' 14"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of about 15 sec.  The peak count rate
was ~700 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 17:35:48.4 UT, 140.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright, fading,
uncatalogued X-ray source located at RA, Dec 266.22043, 15.83309 which
is equivalent to:
   RA(J2000)  = 17h 44m 52.90s
   Dec(J2000) = +15d 49' 59.1"
with an uncertainty of 3.8 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (7.3e+20
cm^-2, Kalberla et al. 2005), with an excess column of 2 (+1.81/-1.60)
x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 6.30e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 149 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  0.11. 

Burst Advocate for this burst is S. T. Holland (Stephen.T.Holland AT 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: GRB100413A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10582
SUBJECT: GRB 100413A: MASTER-Net  optical  observations 
DATE:    10/04/13 19:34:34 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok, O.Gres, O.
Irkutsk State University


K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok, O.Gres, 
O. Chuvalaev
Irkutsk State University

V.Yurkov, 
Yu.Sergienko, D.Varda, A.Garusina Blagoveschensk Educational State 
University, Blagoveschensk


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

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


V.Krushinski, I.Zalozhnih, T.Kopytova, A.Popov
Ural State University, Kourovka




Two MASTER  robotic telescopes (MASTER-Net: http://observ.pereplet.ru, 
testing telescopes)
located at Baykal-Tunka and Blagoveschensk   was responted to the  GRB 
100413A (Swift Bat alert,
  Holland et al, GCN CIRC 10581)   32 sec after   Notice time and  65 s 
after the GRB time.

There is now OT on the first 20-s  exposition time unfiltered images 
inside Swift XRT error box (Holland et al., GCN CIRC 10581)
brighter 17.0 (Blagoveschensk) and 16.6 (Baykal-Tunka).




The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100413A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10583
SUBJECT: GRB 100413: xinglong TNT optical upper limit
DATE:    10/04/13 19:49:41 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L.P. Xin, H. Liu, Y.L. Qiu, J.Y. Wei,J. Wang, J.S. Deng, 
C. Wu, J.Y. Hu, W.K. Zheng on behalf of EAFON report:

We began to observe GRB100413 (Holland et al., GCN 10581, Ivanov et al.
GCN 10582) with Xinglong TNT telescope at 17:44:03(UT),10min 35s after
the burst. A series of white, R band images were obtained. No new source
(Ivanov et al. GCN 10582) is found in the XRT errorbars within the
combined 20*20s white band data. The 3 sigma upper limit is about 20.6
mag  derived from USNO-B1.0,at the mean time of 13 min after the burst.


Further observations are encouraging. 

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: GRB100413A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10584
SUBJECT: GRB 100413A: Enhanced Swift-XRT position
DATE:    10/04/13 20:59:31 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 952 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 100413A, 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 = 266.22175, +15.83400 which is equivalent
to:

RA (J2000): 17h 44m 53.22s
Dec (J2000): +15d 50' 02.4"

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, MNRAS, 397, 1177).

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


GRB_name: GRB100413A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10585
SUBJECT: GRB 100413A: Swift-BAT initial refined analysis
DATE:    10/04/13 21:07:15 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), N. Gehrels (GSFC), S. T. Holland (CRESST/USRA/GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), 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 100413A (trigger #419404)
(Holland, et al., GCN Circ. 10581).  The BAT ground-calculated position is
RA, Dec = 266.223, 15.833 deg, which is 
   RA(J2000)  =  17h 44m 53.4s 
   Dec(J2000) = +15d 50' 00.3" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 48%.
 
The mask-weighted light curve shows multiple overlapping peaks in two main
clusters of peaks.  It starts at ~T-45 sec, with the first cluster ending 
at ~T+40 sec.  The second cluster starts around T+90 sec, peaks around T+100 sec,
and ends later than T+240 sec.  The emission does not return
to background between the two clusters.  We are issuing this refined circular
prior to receiving all the data, because there is a backlog in the downlinking
of the data and it will be many hours until receive the data past T+240 sec.
These results will be updated when we receive the full data set.
 
Using this partial data set, the time-averaged spectrum
from T-1.5 to T+213.1 sec is best fit by a simple power-law model.
The power law index of the time-averaged spectrum is 1.17 +- 0.07.
The fluence in the 15-150 keV band is 6.2 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+116.78 sec in the 15-150 keV band
is 0.7 +- 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/419404/BA/


GRB_name: GRB100413A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10586
SUBJECT: GRB 100413A: Swift-XRT Refined Analysis
DATE:    10/04/14 08:16:31 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 on
behalf of the Swift-XRT team:

We have analysed 5.3 ks of XRT data for GRB 100413A (Holland et al. GCN
Circ. 10581), from 129 s to 30.4 ks after the BAT trigger. The data
comprise 551 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN. Circ 10584).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.53 (+/- 0.07). At T+430 s the decay
flattens to an alpha of 1.20 (+/- 0.04). The light curve breaks again
at T+9980 s to a poorly-constrained final decay with alpha=2.3 (-0.5,
positive error is unconstrained).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.83 (+/-0.06). The
best-fitting absorption column is 2.42 (+0.19, -0.18) x 10^21 cm^-2, in
excess of the Galactic value of 7.3 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.06 (+0.13, -0.12)
and a best-fitting absorption column of 3.1 (+/-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 (7.4 x 10^-11) erg cm^-2
count^-1.

If the light curve continues to decay with a power-law decay index of
2.3, the count rate at T+24 hours will be 2.02 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.1 x
10^-14 (1.5 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/00419404.

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


GRB_name: GRB100413A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10587
SUBJECT: GRB 100413A: SARA upper limit
DATE:    10/04/14 09:29:16 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike, Dieter H. Hartmann (Clemson University), Loris Magnani
(UGA), and Chris De Pree (Agnes Scott College) report:

We observed the field of GRB 100413A (Holland et al., GCN 10581) with the
0.9m SARA-North telescope at KPNO beginning at 06:57 UT on April 14, 2010
(13.4 hours after the trigger) at high airmass and continuing for 40
minutes.  At the location of the enhanced XRT error circle (Goad et al.,
GCN 10584) we do not detect any new sources in stacked I-band images down
to a limiting magnitude of I ~ 19 (as compared to the USNO B1.0 catalog). 
No further observations are planned.


GRB_name: GRB100413A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10588
SUBJECT: Tentative redshift of GRB100413A from X-ray data
DATE:    10/04/14 10:39:40 GMT
FROM:    Sergio Campana at INAF-OAB  <sergio.campana@brera.inaf.it>

S. Campana (INAF-OAB), P.A. Evans (U. Leicester) and S. T. Holland
(CRESST/USRA/GSFC) report on behalf of the Swift-XRT team:

Swift XRT observed GRB 100413A (Holland et al. 2010, GCN 10581)
in Windowed Timing (WT) mode in the 146-550 s time interval.
During this interval the 1.5-10 keV to 0.3-1.5 keV hardness ratio slightly
decayed, testifying for small spectral variations.
We assume a Galactic column density of 7.3x10^20 cm^-2 (Kalberla et
al. 2005, A&A 440 775) and fit the WT spectrum with an absorbed
(tbabs*ztbabs) cutoff power law model within XSPEC (the cutoff power
law model provides much better results in terms of column density 
evaluation
with respect to a simple power law model when small spectral variations 
are present).
Data were grouped to have 30 counts per spectral bin. The resulting fit 
is good
(reduced chi2=0.9, 194 dof).
Filtering the data for single pixel events does not change the results.
In the intrinsic column density vs. redshift plane there is a low 
significance (3 sigma)
solution at low redshifts but the minimum lies at higher redshifts with 
a 2 sigma confidence
level solution of z=3.9+1.7-0.7 and N_H(z)=(5.5+9.8-2.1)x1022 cm-2.
Thus, even if we cannot exclude that GRB100413A is at low redshift, a 
high redshift (z~4),
highly absorbed (N_H(z)~6x1022 cm-2) solution is preferred.
This compares well with the non-detection with UVOT (Holland et al. 
2010) and
other robotic telescopes.

The contour plot is available at
http://www.brera.inaf.it/utenti/campana/100413.gif


GRB_name: GRB100413A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10589
SUBJECT: GRB 100413A: Faulkes Telescope South observations
DATE:    10/04/14 12:39:48 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

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

On 2010 April 13 at 17:37:19 UT the 2-m Faulkes Telescope South
automatically began observing the Swift GRB 100413A
(Holland et al., GCN Circ. 10581) using the BVR, i' filters,
corresponding to 231 s after the burst trigger time.

Inside the XRT error circle (Goad et al. GCN Circ. 10584)
we do not detect any source at the following limiting
magnitudes:

Mid time from    Total Exp   Filter    Magnitude
trigger (min)    (s)
------------------------------------------------
04.52            3x10        R         > 19.8
28.6              540        R         > 22.2
33.2              520        i         > 21.3
------------------------------------------------

Magnitudes have been calibrated from nearby USNOB-1
stars, using the R2 and I magnitudes.


GRB_name: GRB100413A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10590
SUBJECT: Konus-Wind observation of GRB 100413A
DATE:    10/04/14 13:39:18 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 GRB 100413A (Swift-BAT trigger #419404: Holland et al., GCN 
10581; Stamatikos et al., GCN 10585) was detected by Konus-Wind in the 
waiting mode.

The burst light curve shows a multipeaked structure with a total 
duration of ~220 s.

As observed by Konus-Wind, the burst had a fluence of (2.66 +/-
0.23)x10^-5 erg/cm2 (in the 20 - 1200 keV energy range).

Modeling the K-W 3-channel time-integrated spectrum (from T0-3 s to 
T0+212 s) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.01  0.06, Ep = 446 +/- 123 keV.

All the quoted errors are estimated at the 1 sigma confidence level.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB100413A/

Assuming z ~ 3.9 (Campana, Evans, and Holland, GCN 10588) 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 ~8x10^53 erg, and Ep_rest 
~2200 keV.


GRB_name: GRB100413A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10591
SUBJECT: GRB 100413A: Swift/UVOT Upper Limits
DATE:    10/04/14 17:07:25 GMT
FROM:    Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and S.T. Holland (CRESST/USRA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100413A
150 s after the BAT trigger (Holland et al., GCN Circ. 10581).
No optical afterglow consistent with the enhanced XRT position
(Goad et al., GCN Circ. 10584) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC)
exposures and subsequent exposures are:

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

white_FC           150          300          147         >20.5
u_FC               308          558          246         >20.5
white              150         6231          589         >21.8
v                  639         6641          490         >20.4
b                  564         7321          353         >20.7
u                  308         7256          717         >20.7
w1                 688         7051          471         >20.5
m2                 663         6846          490         >20.4
w2                 614         6436          491         >20.8

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: GRB100413A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10592
SUBJECT: GRB 100413A: GROND Upper limits
DATE:    10/04/14 17:10:42 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

Robert Filgas, Thomas Kruehler, Jochen Greiner and Abdullah Yoldas (all 
MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 100413A (Swift trigger 419404; Holland et 
al., GCN #10581) simultaneously in g'r'i'z'JHK with GROND (Greiner et 
al., 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La 
Silla Observatory (Chile).

Observations started at 05:43 UT on April 14, 12 hours after the GRB 
trigger, and continued for 2.5 hours. They were performed at an average 
seeing of 1" under clear sky conditions.

In stacked images of 125 min total integration time in g'r'i'z' and 100 
min in JHK, we do not detect a source within the Swift/XRT error circle 
(Goad et al., GCN #10584) down to the following 3 sigma limiting 
magnitudes (all in the AB system):

g' > 25.3,
r' > 25.2,
i' > 24.6,
z' > 24.3,
J > 22.5,
H > 22.1 and
K > 21.1

These limits were derived by calibrating the images against the GROND 
zeropoints and 2MASS field stars and are not corrected for the Galactic 
foreground extinction corresponding to a reddening of E_(B-V)= 0.11 in 
the direction of the burst (Schlegel et al. 1998).


GRB_name: GRB100413B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10593
SUBJECT: GRB 100413B : Swift detection of a burst
DATE:    10/04/14 18:18:20 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (NASA/GSFC), and 
D. M. Palmer (LANL) report on behalf of the Swift Team:

At 08:42:41 UT on 2010-04-13, BAT detected a rate increase 
GRB 100413B (trigger=419380).  On-board analysis of two 
separate 1.024 second time intervals found sub-threshold peaks (~5 sigma)
at a consistent location in both images, but further on-board analysis was 
truncated by a preplanned slew. Subsequent ground analysis of the data 
improved our confidence in the detection and refined the location to 
RA, Dec = 356.818, +51.321 which is
 RA(J2000)  = 23h 47m 16s
 Dec(J2000) = +51d 19m 18s
with an uncertainty of of 3 arcmin of error (radius, 90% containment, 
including systematic uncertainty).  The BAT light curve shows a single peak 
rising to a peak count rate of ~1800 counts/sec (15-350 keV), at ~12 sec 
after the trigger, with the data truncated by the slew at ~18 sec after the trigger.

A Target of Opportunity observation has been made with the XRT and 
UVOT starting at 31.4 hours after the trigger.  Due to a telemetry backlog, 
data from these observations will not be available until tomorrow.

If this source is confirmed it will mark Swift's 500th GRB.

Burst Advocate for this burst is J. L. Racusin (judith.racusin AT 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: GRB100414A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10594
SUBJECT: GRB100414A: Fermi LAT detection
DATE:    10/04/14 22:23:42 GMT
FROM:    Nicola Omodei at INFN(Pisa)/GLAST  <nicola.omodei@pi.infn.it>

Hiromitsu Takahashi (Hiroshima Univ.), Masanori Ohno (ISAS/JAXA), Nicola Omodei (Stanford Univ.) report on behalf of the Fermi Large Area Telescope collaboration

At 02:20:21 UT on 14th April 2010, the Fermi Large Area Telescope (LAT) detected gamma rays from the long GRB 100414A, which was triggered  and located by the Fermi Gamma-ray Burst Monitor (GBM) (trigger 292904423/100414.097). 

At the time of the trigger the GRB was approximately at 70 degrees with respect to the LAT boresight which is close the edge of the LAT field of view. 
The GBM trigger caused an Autonomous Repoint Request, and the spacecraft moved to point at the GBM location.
The data from the Fermi LAT show significantly detected emission from a transient point source as late as 300 seconds after the GBM trigger.
The best LAT on-ground localization is found to be RA,Dec= 191.59, 8.57; (12:46:21.60, 08:34:12.0, J2000)  with a 90% containment radius of 0.18 deg (statistical; 68% containment radius: 0.14 deg, preliminary systematic error is less than  0.1 deg). 

More than 20 photons above 100 MeV are observed within 300 seconds, and the highest energy photon coincident with the GRB position is a 4 GeV event which is observed 40 seconds after the GBM trigger.

Further analysis is ongoing.

The point of contact for this burst is Hiromitsu Takahashi
(hirotaka@hep01.hepl.hiroshima-u.ac.jp)

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: GRB100414A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10595
SUBJECT: GRB 100414A: Fermi GBM detection
DATE:    10/04/14 23:06:12 GMT
FROM:    Suzanne Foley at MPE  <sfoley@mpe.mpg.de>

S. Foley (MPE) reports on behalf of the Fermi GBM Team:

"At 02:20:21.99 UT on 14 April 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100414A (trigger 292904423 / 100414097).
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 = 184.51, DEC = 9.65 (J2000 degrees,
equivalent to 12 h 18 m, 09 d 39 '), with an uncertainty
of 1.0 degree (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 65 degrees.

The GBM light curve consists of one main pulse
with a duration (T90) of about 26.4 (+/-1.6) s (50-300 keV).
The time-averaged spectrum from T0+2.3 s to T0+28.9 s is
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.58 (+/- 0.01) and
the cutoff energy, parameterized as Epeak, is 627.6 (+12.5/-12.1)
keV (CSTAT 1075.2 for 480 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.29 +/- 0.02)E-4 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+22.8 s in the 8-1000 keV band
is 18.22 +/- 0.24 ph/s/cm^2.


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


GRB_name: GRB100415A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10596
SUBJECT: GRB 100415A: MAXI/GSC detection of a probable GRB
DATE:    10/04/15 12:42:26 GMT
FROM:    Motoko Suzuki at RIKEN  <motoko@crab.riken.jp>

T. Sootome, T. Mihara, Y.E. Nakagawa, M. Sugizaki, 
M. Suzuki, T. Yamamoto (RIKEN), M. Matsuoka, 
K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA),
N. Kawai, M. Morii, K. Sugimori (Tokyo Tech),
A. Yoshida, K. Yamaoka,  S. Nakahira (AGU),
H. Tsunemi, M. Kimura (Osaka U.), H. Negoro, M. Nakajima
H. Ozawa, F. Suwa (Nihon U.), Y. Ueda, N. Isobe, 
S. Eguchi, K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), A. Uzawa, 
T. Matsumura, K. Yamazaki (Chuo U.) report on behalf of the MAXI team:

At the scan transit centered at UT 2010-04-15T03:44:57,
MAXI/GSC detected a short X-ray transient lasting about 23 seconds 
within the 50 seconds triangular transit response of MAXI/GSC.$B!!(B
Judging from its location and spectral hardness ratio, this transient is
probably a gamma-ray burst.

Since the emission was detected only for a fraction of the triangular 
transit response, the uncertainty of its position along the scan direction 
is large.  Without assuming the source constancy, we obtain a rectangular 
error box (90%C.L.) with the following corners: 

(R.A., Dec) = (+7.48 deg, -15.57 deg) = (00 29 55, -15 34 12)(J2000)
(R.A., Dec) = (+6.91 deg, -15.86 deg) = (00 27 38, -15 51 36)(J2000)
(R.A., Dec) = (+7.92 deg, -17.25 deg) = (00 31 41, -17 15 00)(J2000)
(R.A., Dec) = (+8.49 deg, -16.96 deg) = (00 33 58, -16 57 36)(J2000)

There is additional systematic uncertainty of 0.2 deg (90% containment radius).

The preliminary flux (4-10 keV) of the source was at least 170 mCrab.
There was no significant detection at the transit location in the
previous and following orbits (92 min before or after the detection) 
with an upper limit of 20 mCrab.  There is no known bright X-ray source 
at the detected position. 

Follow-up observations are encouraged.


GRB_name: GRB100414B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10597
SUBJECT: Konus-Wind observation of GRB 100414B
DATE:    10/04/15 13:11:12 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long bright hard GRB 100414B (localized by Fermi-LAT;
Takahashi et al., GCN 10594) triggered Konus-Wind
at T0=08427.289s UT (02:20:27.289)

The burst light curve consists of a single slowly
rising pulse which ends abruptly after a culmination
at T0+22.528. A total duration of the burst is ~25 s.
No spectral evolution is apparent in the course of the burst.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB100414_T08427/

As observed by Konus-Wind the burst
had a fluence of 1.06(+/-0.06)x10-4 erg/cm2,
and a 256-ms peak flux measured from T0+22.528s
of 8.6(+/-0.6)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+25.856 s) is well fitted
in the 20 keV - 5 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.46 (-/+0.07),
the high energy photon index beta = -3.2(-1.5, +0.4),
the peak energy Ep = 547(-21, +22)keV (chi2 = 97/76 dof).

The spectrum at the maximum count rate
(measured from T0+19.200 to T0+25.586 s) is best fit
in the 20 keV - 5 MeV range by a power law
with exponential cutoff model, for which
alpha = -0.81(+/-0.1),
and Ep = 595(-62, +75) keV (chi2 = 75/77 dof).

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


GRB_name: GRB100414A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10598
SUBJECT: Konus-Wind observation of GRB 100414A (correction to GCN 10597)
DATE:    10/04/15 13:26:42 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, on behalf of Konus-Wind team, report:

The correct designation of the burst reported in the GCN 10597
is GRB 100414A (not GRB 100414B).


GRB_name: GRB100414A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10599
SUBJECT: GRB 100414A:  IPN Localization
DATE:    10/04/15 22:05:36 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

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,

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

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

and K. Hurley

report:

The long GRB 100414A, seen by Fermi/LAT (Takahashi et al., GCN 10594)
Fermi/GBM (Foley, GCN 10595), and Konus-Wind (Golenetskii et al., GCN
10597) was also detected by Suzaku WAM so far.

Triangulation gives a Konus-WAM annulus centered at RA(2000)=223.490
(14h 53m 58s)  Dec(2000)=-18.645 (-18d 38' 42"), whose
radius is 41.329  0.588 deg (3 sigma);
and a Konus-GBM annulus centered at RA(2000)=223.527 (14h 54m 06s)
Dec(2000)=-18.436 (-18d 26' 09"), whose radius is 41.123  0.262  deg
(3 sigma).  These annuli are parallel and cannot be used to
define a small error box.  The Konus-GBM annulus is entirely contained
within the the Konus-WAM annulus in the region around the Fermi/LAT
localization.

The center of the LAT position (RA,Dec,Err = 191.59, 8.57, 0.18 deg)
is 0.377 deg from the center line of the annulus.

A figure of the triangulated localization can be seen at:

http://gammaray.nsstc.nasa.gov/gbm/science/ipn_plots/GRB100414A_IPN.png

This localization may be refined with the arrival of data from more
distant spacecraft.

Swift is following up this localization using information from the IPN
triangulation and further processing from the Fermi LAT team.


GRB_name: GRB100413A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10600
SUBJECT: GRB 100413A: Swift-BAT final refined analysis
DATE:    10/04/15 23:08:38 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC), S. T. Holland (CRESST/USRA/GSFC)
(for the Swift-BAT team):
 
The full data set for this burst has been downlinked.
Using the data set from T-239 to T+963 sec, we report final analysis
of BAT GRB 100413A (trigger #419404) (Holland, et al, GCN Circ 10581
and Stamatikos, GCN Circ 10585).  The BAT ground-calculated position is
RA, Dec = 266.223, 15.835 deg, which is 
   RA(J2000)  =  17h 44m 53.6s 
   Dec(J2000) = +15d 50' 04.6" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 48%.
 
The mask-weighted light curve shows multiple overlapping peaks in two main
clusters of peaks.  It starts at ~T-45 sec, with the first cluster ending
at ~T+40 sec.  The second cluster starts around T+90 sec, peaks around T+100 sec,
and ends at ~T+250 sec.  The emission does not return to background
between the two clusters.  T90 (15-350 keV) is 191 +- 14 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-3.4 to T+227.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.25 +- 0.07.  The fluence in the 15-150 keV band is 6.2 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+116.78 sec in the 15-150 keV band
is 0.7 +- 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/419404/BA/


GRB_name: GRB100414A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10601
SUBJECT: GRB 100414A: Swift-XRT detection of a possible X-ray afterglow
DATE:    10/04/16 20:02:44 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page (U. Leicester), J. L. Racusin (NASA/GSFC), J.A. Kennea (PSU) and 
J.K. Cannizzo (NASA/UMBC) report on behalf of the Swift-XRT team:

Following a Target of Opportunity request, Swift started observing the 
field of the Fermi GBM- and LAT-detected GRB 100414A about 48 hours after 
the trigger (GCN Circs. 10594, 10595). In 1.4 ks of data there is an 
uncatalogued source detected within the XRT field of view, at a position 
of RA, Dec = 192.11199, 8.69172, which is equivalent to

RA (J2000):   12 48 26.88
Dec (J2000): +08 41 30.2

with an uncertainty of 3.8 arcsec (radius, 90% containment).

The source is at a count rate of 0.022 +/- 0.004 count s^-1 (0.3-10 keV), 
corresponding to an observed flux of ~1.31x10^-12 erg cm^-2 s^-1; however, 
with the limited data collected so far, it is not possible to determine 
whether this source is fading.


GRB_name: GRB100413B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10602
SUBJECT: GRB 100413B: Swift Confirmation of Burst
DATE:    10/04/16 20:56:27 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC), S. D. Barthelmy (NASA/GSFC), J. Cummings  
(GSFC/UMBC), P. A. Evans (U. Leicester), N. Gehrels (NASA/GSFC), W. B.  
Landsman (NASA/GSFC), O. M. Littlejohns (U. Leicester), F. .E.  
Marshall (NASA/GSFC), K. L. Page (U. Leicester), D. Palmer (LANL)  
report on behalf of the Swift team:

After further analysis of the BAT ground detected GRB 100413B (Racusin  
et al., GCN 10593), we can now confirm that it is a real burst.  It  
was detected at the level of 12.4 sigma in 10 seconds of data.  The  
light curve shows a peak beginning at ~T-7 sec, and lasting until at  
least T+18 sec, when the spacecraft slewed away from the burst due to  
a pre-planned target.

Our best position is the BAT ground calculated RA/Dec = 356.8264,  
+51.2704 deg, which is
    RA(J2000) = 23h 47m 18.3s
    Dec(J2000) = +51d 16' 13.4"
with an uncertainty of 2 arcmin (radius, 90% containment, including  
systematic uncertainty).

The time-averaged spectrum from T-2 to T+8 sec is best fit by a power- 
law with an exponential cutoff.  The fit gives a power law index of  
-0.5+/-0.4, and an Epeak of 28+/-6 keV.  The fluence in the 15-150 keV  
band is (4.3 +/- 0.4) x10^-7 ergs cm-2.  All the quoted errors are at  
the 90% confidence level.

GRB 100413B was also detected by Konus-Wind in the waiting mode (V.  
Pal'shin, private communication).

A Target of Opportunity observation began ~31.5 hours after the BAT  
trigger.  In 16.5 ks of XRT data, no X-ray afterglow was detected down  
to a limit of 1.6 x 10^-3 counts s-1 (3-sigma).  Assuming an average  
observed flux to counts conversion factor of 3.8 x 10^-11 (Evans et  
al., 2009, MNRAS, 397, 1177), this corresponds to a flux limit of 6 x  
10^-14 erg cm-2 s-1.  Given the late start to follow-up observations  
and exposure time, the lack of a X-ray counterpart is not surprising.

Preliminary 3-sigma upper limits using the UVOT photometric system  
(Poole et al. 2008, MNRAS, 383, 627) from a 2538 sec u band image  
taken 31.4 hours after the burst shows no new source within the BAT  
error circle with a limit of u > 21.4.  This value is not corrected  
for the Galactic extinction due to the reddening of E(B-V) = 0.19 in  
the direction of the burst (Schlegel et al. 1998).


GRB_name: GRB100414A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10603
SUBJECT: GRB 100414A: Palomar Transient Factory Observations
DATE:    10/04/16 22:06:46 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko (UC Berkeley), A. Rau (MPE Garching), E. O. Ofek (Caltech),
P. E. Nugent (LBNL), J. Greiner (MPE Garching), and S. R. Kulkarni
(Caltech) report on behalf of a larger collaboration:

We have imaged the Fermi-LAT localization of GRB 100414A (Takahashi et
al., GCN 10594; Foley, GCN 10595) with the automated Palomar 48 inch
Schmidt telescope as part of the Palomar Transient Factory (PTF; Law et
al, PASP, 1395; Rau et al, PASP 121, 1334) survey.  A 60 s R-band image
was obtained beginning at 7:53 UT on 15 April 2010 (~ 29.5 hours after the
burst trigger), followed approximately an hour later by another 60 s image
of the identical field.

Digital subtraction with respect to a stacked pre-explosion P48 reference
image reveals no afterglow candidate to a limiting magnitude of R > 21.0
mag within the 90% LAT localization region (Takahashi et al., GCN 10594).

We note, however, that our imaging does not cover the location of the
potential XRT afterglow candidate identified by Page et al. (GCN 10601).


GRB_name: GRB100413A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10604
SUBJECT: GRB 100413A: Suzaku WAM observation of the prompt emission
DATE:    10/04/17 06:53:33 GMT
FROM:    Satoshi Sugita at Aoyama Gakuin U.  <sugita@phys.aoyama.ac.jp>

S. Sugita (Nagoya U.), K. Yamaoka (Aoyama  Gakuin U.), M. Ohno,
M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa, M. Suzuki,
T. Tamagawa (RIKEN), N. Vasquez (Tokyo Tech.), Y. Urata, H.M. Lin,
P. Tsai (NCU), Y. Nishioka, N. Ohmori, A. Daikyuji, E. Sonoda, K. Kono,
K. Noda, M. Yamauchi (Univ. of Miyazaki), T. Sugasahara, M. Tashiro,
Y. Terada, W. Iwakiri (Saitama U.), Y. Hanabata, T. Uehara,
T. Takahashi, Y. Fukazawa (Hiroshima U.), T. Enoto, K. Nakazawa,
K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.),
on behalf of the Suzaku WAM team, report

The very long GRB 100413A (Swift/BAT trigger #419404 ;
Holland et al., GCN 10581)

was detected by the the Suzaku Wide-band  All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 2010-04-13 17:33:28 UT
(=T0).

The observed light curve shows a multi-peaked structure
 lasting to T0+220s with a duration T90 of about 160 seconds.
The fluence in 100 - 1000 keV was 1.59 (-0.83, +0.21) x10^-5 erg/cm^2.
 The 1-s peak flux measured from T0+118s was 0.38 (-0.27, +0.14)
photons/cm^2/s in the same  energy range.

Preliminary result shows that the time-averaged spectrum from
T0-2s to T0+213s is well fitted by a power-law with exponential
cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha       -0.59 (-1.64, +1.27), and
  Epeak       364 (-55, +98) keV (chi^2/d.o.f. = 37.9/30).

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

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: GRB100414A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10605
SUBJECT: GRB 100414A: Enhanced Swift-XRT position of candidate afterglow
DATE:    10/04/17 07:37:24 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the 
Swift-XRT team:

Using 3686 s of XRT Photon Counting mode data and 3 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 = 
192.11266, 8.69309 which is equivalent to:

RA (J2000):  12 48 27.04
Dec (J2000): +08 41 35.1

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

This position may be improved as more data are received. Position 
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans 
et al. (2009, MNRAS, 397, 1177).

Please note that we still cannot confirm that this source is fading.

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


GRB_name: GRB100414A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10606
SUBJECT: GRB 100414A: Gemini-N candidate and redshift
DATE:    10/04/17 08:16:49 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara and D. B. Fox  (PSU) report on behalf of
a larger collaboration:

"Starting on 2010 April 17.26 UT we used the GMOS spectrograph
on the Gemini North 8-m telescope to observe the field of the
Fermi-LAT GRB 100414A (Takahashi et al. GCN 10594).

In our 5 min i'-band observation we detected a bright source
inside the refined XRT error circle (Page et al., GCN 10605)
at the following coordinate:

RA: 12:48:29.96
Dec: +8:41:34.91

with 0.5" uncertainty in both directions.

Using two USNO-B1 stars we obtain i' = 20.37 +- 0.03 mag for this
object.
A sequence of 2x1200s spectra were also obtained with the same
instrument, covering a spectral range of 4000-8000A.

A series of metal absorption features were identified (FeII2374,
FeII2383,FeII2587,MnII2594, FeII2600, MgII2796,2803,MgI2853) at
the common redshift of z= 1.368.

We therefore suggest this as the redshift of GRB 100414A.
Further observations are planned.

We thank the Gemini staff for performing this observation,
in particular A. Fritz."


GRB_name: GRB100414A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10607
SUBJECT: GRB 100414A: GROND Detection of the Optical Afterglow
DATE:    10/04/17 09:53:25 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

Robert Filgas, Thomas Kruehler and Jochen Greiner (all MPE Garching) 
report on behalf of the GROND team:

We observed the field of GRB 100414A (Fermi GBM/LAT trigger
292904423/100414.097; Takahashi et al., GCN #10594, Foley, GCN #10595) 
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 
405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile).

Observations started at 03:11 UT on April 17, 73 hours after the GRB
trigger, and were performed through thick cloud coverage.

We detect the optical afterglow reported by Cucchiara & Fox (GCN #10606) 
in the optical bands. To reiterate the position, we measure

RA (J2000) = 12 h 48 m 26.93 s
DEC (J2000) = +08d 41' 34.4"

with an uncertainty of 0.5" in each coordinate against SDSS astrometry 
and inside the enhanced XRT error circle reported by Page et al. (GCN 
#10605).

Based on 4 min of total exposure, we estimate preliminary magnitudes 
(all in AB system) of

g' = 21.3 +- 0.1 mag,
r' = 20.9 +- 0.1 mag

Given magnitudes are calibrated against SDSS field stars and are not
corrected for the expected Galactic foreground extinction corresponding 
to a reddening of E_(B-V)=0.03 mag in the direction of the burst 
(Schlegel et al. 1998).


GRB_name: GRB100414A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10608
SUBJECT: GRB 100414A: Gemini-N observation (correction)
DATE:    10/04/17 14:40:20 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara (PSU) reports on behalf of a larger collaboration:

"We noted a typo in the coordinate reported in GCN 10606.
The correct position of the GRB 100414A optical transient
in our Gemini-N image is:

RA: 12:48:26.96
Dec: +08:41:34.91

We thank W. Landsman for pointing this out to us and we
apologize for any confusion this may have caused."


GRB_name: GRB100414A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10609
SUBJECT: GRB 100414A: Swift/UVOT Observations
DATE:    10/04/17 15:56:44 GMT
FROM:    Wayne Landsman at GSFC/SSAI  <wayne.b.landsman@nasa.gov>

W. Landsman (GSFC) and J. Cannizzo  (GSFC) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT began observations of the field of GRB 100414A 40.4 hours 
after the Fermi LAT and GBM-detected trigger (Takahashi et al. GCN Circ. 
10594, Foley et al., GCN Circ. 10595).     We detect the source reported 
by Cucchiara & Fox (GCN Circ. 10606, 10608) and Filgas et al. (GCN Circ. 
10607)    Combining our white observations into exposures beginning at 
40.4 and 53.2 hours, we find evidence for source fading.

Filter    T_start (hr)   Exp(s)     Mag     Err
White      40.38          765      20.54 +/- 0.10
White      53.20         3531      20.86 +/- 0.06

These observations are not corrected for the expected Galactic 
foreground extinction corresponding to a reddening of E_(B-V)=0.03 mag 
in the direction of the burst (Schlegel et al. 1998).    The photometry 
is on the UVOT photometric system described in Poole et al.(2008, MNRAS, 
383,627).


GRB_name: GRB100414A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10610
SUBJECT: GRB 100414A: Suzaku WAM observation of the prompt emission
DATE:    10/04/17 19:42:41 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka@phys.aoyama.ac.jp>

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

The bright long, Fermi-LAT GRB 100414A (Takahashi et al., GCN 10594; 
Fermi/GBM trigger #292904423 / 100414097; Foley, GCN 10595) triggered the 
Suzaku Wide-band  All-sky Monitor (WAM) which covers an energy range 
of 50 keV - 5 MeV at 02:20:22.879 UT (=T0). 

The observed light curve shows a multi-peaked structure starting at T0-1.5 s,
 ending at T0+24.5 s with a duration (T90) of about 22 seconds. 
 The fluence in 100 - 1000 keV was 4.88(-0.36, +0.13)x10-5 erg/cm^2. 
 The 1-s peak flux measured from T0+22.5 s was 6.13(-0.79, +0.40) 
  photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from 
T0-1.5 s to T0+24.5 s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -0.56(-0.29, +0.37),
the high-energy photon index beta: -3.05(-0.53, +0.30),
and the peak energy Epeak: 612(-53, +55) keV (chi^2/d.o.f = 34/23).

Due to the brightness of this burst, a 3% systematic error was 
 added for low energy channels.  In addition, there might be 
  some calibration uncertainties in these spectral parameters 
 because GRB photons came to the WAM detector by passing through the 
  large Ne dewar of the X-ray micro-calorimeter (XRS). 
All the errors are quoted at 90% confidence level.

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: GRB100413A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10611
SUBJECT: GRB 100413A:  Radio Afterglow Detection with the EVLA 
DATE:    10/04/17 23:59:34 GMT
FROM:    Derek Fox at PSU  <dfox@astro.psu.edu>

Dale A. Frail (NRAO) and Derek Fox (PSU) report on behalf of a larger
collaboration:

"We used the Expanded Very Large Array (EVLA) to observe the
localization of the Swift burst GRB 100413A (Trigger #419404; Holland
et al., GCN 10581), an X-ray bright event without any optical or NIR
counterpart to deep limits (Xin et al., GCN 10583; Updike et al., GCN
10587; Guidorzi et al., GCN 10589; Filgas et al., GCN 10592). Within
the revised XRT error circle (Goad et al., GCN 10584) we detect a
single 8.5 GHz radio source with flux density 159 +/- 15 uJy and
position R.A. 17:44:53.16, Dec. +15:50:03.2 (J2000), with 1-sigma
astrometric uncertainty of +/-0.6 arcsec.

The EVLA is undergoing active commissioning and as such these results
should be considered preliminary. 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: GRB100418A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10612
SUBJECT: GRB 100418A: Swift detection of a burst with a possible optical afterglow
DATE:    10/04/18 21:27:58 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

F. E. Marshall (NASA/GSFC), A. P. Beardmore (U Leicester),
J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
O. M. Littlejohns (U Leicester), C. B. Markwardt (CRESST/GSFC/UMD),
P. T. O'Brien (U Leicester), C. Pagani (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
A. Rowlinson (U Leicester), M. C. Stroh (PSU),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 21:10:08 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100418A (trigger=419797).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 256.376, +11.464 which is 
   RA(J2000) = 17h 05m 30s
   Dec(J2000) = +11d 27' 50"
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 4 sec.  The peak count rate
was ~700 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 21:11:27.1 UT, 79.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
256.3635, 11.4619 which is equivalent to:
   RA(J2000)  = 17h 05m 27.24s
   Dec(J2000) = +11d 27' 42.7"
with an uncertainty of 3.1 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
4.78e+20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 1.27e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White   
filter  starting 87 seconds after the BAT trigger. A possible   
afterglow candidate has  been found in the initial data products at   
the location of the XRT afterglow.  The preliminary UVOT position is  

   
    RA(J2000) =  17:05:26.96  =  256.36233 (deg)   
   Dec(J2000) = +11:27:41.9   =  +11.46164 (deg)

with an  estimated uncertainty of 1.0 arcsec (radius, 90% confidence,  
statistical + systematic).  The estimated white magnitude is  20.7 +/-
0.3.  No correction has  been made for the expected extinction  
corresponding to E(B-V) of   0.07. 

Burst Advocate for this burst is F. E. Marshall (marshall 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: GRB100418A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10613
SUBJECT: GRB 100418A: ROTSE-III Optical Limits
DATE:    10/04/18 21:35:05 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship@umich.edu>

S. B. Pandey (U Mich), W. Zheng (U Mich), Limin Xiao (Louisiana State) and
T. Guver (U Arizona), report on behalf of the ROTSE collaboration:

ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe,
Turkey, responded to GRB 100418A (Swift trigger 419797), producing images
beginning 4.6 s after the GCN notice time. An automated response took the
first image at 21:10:30.5 UT, 16.7 s after the burst, and during the
gamma-ray emission, under fair conditions. We took 10 5-sec, 10 20-sec and
10 60-sec exposures. These unfiltered images are calibrated relative to
USNO A2.0 (R). Imaging is on going.

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. Individual images have limiting
magnitudes ranging from 15.1-16.2; we set the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
21:10:30.6   21:10:35.6         5     15.4           16.7       N
21:10:30.6   21:12:37.9       127     16.8           16.7       Y

Further observations are ongoing.


GRB_name: GRB100418A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10614
SUBJECT: GRB 100418A: Enhanced Swift-XRT position
DATE:    10/04/19 00:40:50 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 1381 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 100418A, 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 = 256.36327, +11.46114 which is equivalent
to:

RA (J2000): 17h 05m 27.18s
Dec (J2000): +11d 27' 40.1"

with an uncertainty of 1.9 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, MNRAS, 397, 1177).

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


GRB_name: GRB100418A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10615
SUBJECT: GRB 100418A: Swift-BAT refined analysis
DATE:    10/04/19 01:00:52 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), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 100418A (trigger #419797)
(Marshall, et al., GCN Circ. 10612).  The BAT ground-calculated position is
RA, Dec = 256.358, 11.457 deg, which is 
   RA(J2000)  =  17h 05m 25.8s 
   Dec(J2000) = +11d 27' 26.8" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 49%.
 
The mask-weighted light curve shows two overlapping peaks starting at ~T-10 sec,
peaking at ~T+2 sec, and ending at ~T+40 sec.
T90 (15-350 keV) is 7.0 +- 1.0 sec (estimated error including systematics).
 
The time-averaged spectrum from T-1.1 to T+7.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.16 +- 0.25.  The fluence in the 15-150 keV band is 3.4 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.47 sec in the 15-150 keV band
is 1.0 +- 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/419797/BA/


GRB_name: GRB100418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10616
SUBJECT: GRB 100418A: GROND observations
DATE:    10/04/19 06:01:52 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose@tls-tautenburg.de>

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 100418A (Marshall et al. 2010, GCN 10612) on 
Apr 19, at 4:50 UT (about 7.5 hrs after the burst).

Within the enhanced XRT 1.9 arcsec error circle reported by Osborne et al. 
(GCN 10614) we find a fading point source at coordinates RA, DEC (J2000) =

17:05:27.09,
11:27:42.3

with an uncertainty of 0.5" in each coordinate and estimate the following 
preliminary magnitudes (in the AB system):

g' = 19.2 +- 0.1 
r' = 18.8 +- 0.1
i' = 18.4 +- 0.1
z' = 18.1 +- 0.1
J  = 17.7 +- 0.1

Given magnitudes are calibrated against SDSS field stars and are not 
corrected for the expected Galactic foreground extinction corresponding to 
a reddening of E_(B-V)=0.07 mag in the direction of the burst (Schlegel et 
al. 1998).


GRB_name: GRB100418A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10617
SUBJECT: GRB 100418A: GROND observations; missing author list added
DATE:    10/04/19 06:06:19 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose@tls-tautenburg.de>

R. Filgas (MPE Garching), S. Klose (TLS Tautenburg),
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 100418A (Marshall et al. 2010, GCN 10612) on Apr 19, at 
4:50 UT (about 7.5 hrs after the burst).

Within the enhanced XRT 1.9 arcsec error circle reported by Osborne et al. 
(GCN 10614) we find a fading point source at coordinates RA, DEC (J2000) =

17:05:27.09,
11:27:42.3

with an uncertainty of 0.5" in each coordinate and estimate the following 
preliminary magnitudes (in the AB system):

g' = 19.2 +- 0.1
r' = 18.8 +- 0.1
i' = 18.4 +- 0.1
z' = 18.1 +- 0.1
J  = 17.7 +- 0.1

Given magnitudes are calibrated against SDSS field stars and are not 
corrected for the expected Galactic foreground extinction corresponding to a 
reddening of E_(B-V)=0.07 mag in the direction of the burst (Schlegel et al. 
1998).


GRB_name: GRB100414A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10618
SUBJECT: GRB100414A: SAO RAS optical observations
DATE:    10/04/19 07:34:18 GMT
FROM:    Vladimir Sokolov at SAO RAS  <sokolov@sao.ru>

A. Moskvitin, T. Fatkhullin, V. Sokolov (SAO RAS Niznijh Arkhyz, Russia),
on behalf of a larger colaboration, report:

We observed an OT (Cucchiara & Fox, GCN Circ. 10606, 10608;
Filgas, Kruehler & Greiner, GCN Circ. 10607; Landsman & Cannizzo,
GCN Circ. 10609) of GRB 100414A with the Zeiss-1000 telescope
of SAO RAS, Russia. Observations started 87.31 hours after
the Fermi LAT and GBM triggers (Takahashi et al., GCN Circ. 10594;
Foley, GCN Circ. 10595). We obtained 12 x 300 sec images both in Rc
and V bands with the airmass 1.2-1.7 under good weather conditions.
Calibration was carried out with 8 SDSS nearby stars, whose magnitudes
were transformed according to formulae from
http://www.sdss.org/dr5/algorithms/sdssUBVRITransform.html (Lupon 2005).

Rc = 21.40 +/- 0.09 (17:39:01 -- 19:05:27 UT, mean epoch = April, 17.765),
V = 21.75 +/- 0.08 (19:08:49 -- 20:31:05 UT, mean epoch = April, 17.826).

These magnitudes are not corrected for the expected Galactic extinction
reported in Landsman & Cannizzo, GCN Circ. 10609.
This message may be cited.


GRB_name: GRB100418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10619
SUBJECT: GRB 100418A: SARA observations
DATE:    10/04/19 08:03:11 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike, Dieter H. Hartmann (Clemson University), and Brian Murphy
(Butler University) report:

We observed the field of GRB 100418A (Marshall et al., GCN 10612) using
the 0.9m SARA telescope located at KPNO beginning 10 hours and 18 min
after the trigger.  We detect the afterglow (Filgas et al., GCN 10617) in
our first 10 min exposure at high airmass (2.1) at a magnitude of R = 18.3
upon comparison to the USNO B1.0 catalog.  Observations are continuing.


GRB_name: GRB100418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10620
SUBJECT: GRB100418A: VLT/X-shooter redshift and photometry
DATE:    10/04/19 08:56:13 GMT
FROM:    Stefano Covino at Brera Astronomical Observatory  <stefano.covino@brera.inaf.it>

L.A. Antonelli, J.R. Maund, E. Palazzi, P. Goldoni, S.D. Vergani, H. Flores, A. de Ugarte Postigo, S. Covino, J. Fynbo, J. Hjorth, D. Malesani, J. Sollerman, C.C. Thoene, on  behalf of the X-shooter GRB collaboration report:



We observed the field of GRB 100418A (Marshall et al. 2010, GCN 10612) with VLT/X-Shooter at Cerro Paranal (Chile). The observation started on Apr 19, at 5:32 UT (about 8.37 hrs after the burst) under very good observing conditions (seeing about 0.7").  The object reported by Filgas and Greiner (GCN 10617) is clearly seen in our image at flux level of R = 18.1+/- 0.1 mag calibrated against USNO B.1 catalog. 

Spectra were acquired and in a preliminary analysis they show an abundance of UV absorption lines (Fe II, Mg II, Mg I, Mn II, Ca H,K) as well as [O II] emission at z = 0.6235 (wavelength calibration was obtained with archive calibration data).

We acknowledge the Paranal staff for the support.


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10621
SUBJECT: GRB 100418A: host galaxy detection in the SDSS
DATE:    10/04/19 10:32:36 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

Daniele Malesani (DARK/NBI) reports:

At the position of the optical afterglow of GRB 100418A (Marshall et 
al., GCN 10612; Filgas et al., GCN 10617), a  faint, compact object is 
well visible in the SDSS frames and catalogs ( Abazajian et al. 2009, 
ApJS, 182, 543), in the g, r, and i bands.

The (AB) model magnitudes as reported in the SDSS catalog are:

u: not detected
g = 22.89 +- 0.17
r = 22.41 +- 0.16
i = 21.94 +- 0.17
z: not detected

See e.g. 
http://cas.sdss.org/astrodr7/en/tools/explore/obj.asp?id=758879770841908118

The host detection is consistent with the relatively low redshift and 
the report of nebular emission lines superimposed on the bright 
afterglow continuum (Antonelli et al., GCN 10620). A SN as bright as 
SN1998bw would peak at r ~ 24 at the position of GRB 100418A.


GRB_name: GRB100418A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10622
SUBJECT: GRB 100418A: Swift-XRT Refined Analysis
DATE:    10/04/19 12:05:00 GMT
FROM:    Claudio Pagani at U of Leicester  <cp232@star.le.ac.uk>

C. Pagani (U. Leicester), A. P. Beardmore (U. Leicester)  and F. E.
Marshall (NASA/GSFC) report on behalf of the Swift-XRT team:

We have analysed 3.7 ks of XRT data for GRB 100418A (Marshall et al. GCN
Circ. 10612), from 70 s to 7.3 ks after the BAT trigger. The data
comprise 97 s in Windowed Timing (WT) mode (the first 7 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN. Circ 10614).

The light curve can be modelled with an initial power-law decay with an
index of alpha=4.23 (+0.17, -0.16), followed by a break at T+474 s to an
alpha of 0.21 (+0.22, -0.24).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 4.29 (+0.33, -0.30). The
best-fitting absorption column is 2.1 (+/-0.4) x 10^21 cm^-2, in excess
of the Galactic value of 4.8 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 2.0 x 10^-11 (1.3 x 10^-10) erg cm^-2
count^-1.

If the light curve continues to decay with a power-law decay index of
0.21, 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 2.5 x
10^-13 (1.6 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/00419797.

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


GRB_name: GRB100413A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10623
SUBJECT: GRB 100413A: GMRT observation of radio afterglow
DATE:    10/04/19 13:59:21 GMT
FROM:    Sayan Chakraborti at TIFR,Mumbai,India  <sayan@tifr.res.in>

Sayan Chakraborti, Naveen Yadav and Alak Ray (Tata Institute of
Fundamental Research, Mumbai, India) report:

We observed the optically dark GRB 100413A, whose radio afterglow has
been detected by the EVLA at 8.5 GHz (Frail et al, GCN 10611), with
the Giant Metrewave Radio Telescope (GMRT) on April 19.1 UT. We do
not find, any source at its position, at the observing frequency of
1.28 GHz, down to the 3 sigma upper limit of 124 uJy.

We thank the staff of the GMRT that made this observation possible.
GMRT is run by the National Centre for Radio Astrophysics of the Tata
Institute of Fundamental Research.


GRB_name: GRB100418A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10624
SUBJECT: GRB 100418A: Gemini-N redshift confirmation
DATE:    10/04/19 14:51:54 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara and D. B. Fox (PSU) report on behalf of a
larger collaboration:

"Starting on 2010 April 19.41 UT we used the GMOS spectrograph
on the Gemini North 8-m telescope to observe the field of the
Swift GRB 100418A (Marshall et al. GCN 10612).

A sequence of 2x1200s spectra were obtained covering the
spectral range of 4000-8000A.

A series of metal absorption features were identified (MgII2796,
2803,FeI3720, Ca H&K, CaI4227) and H-beta in emission at the
common redshift of z= 0.624, confirming the previously reported
result of Antonelli et al. GCN 10620.


We thank the Gemini staff for performing this observation,
in particular A. Fritz."


GRB_name: GRB100418A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10625
SUBJECT: GRB 100418A: Swift/UVOT Observations
DATE:    10/04/19 21:54:40 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and F. Marshall (NASA/GSFC) report on behalf
of the Swift/UVOT team.

The Swift/UVOT began settled observations of the field of GRB
100418A 87s after the BAT trigger (Marshall et al., GCN Circ. 10612).
Data summed from the first and second orbits reveals the source
reported by Marshall et al.  The source shows no fading between
the first and second orbits within the photometric uncertainties.
The photometry is consistent with a constant source with a white
magnitude of 20.48+-0.13.  This likely represents the GRB host
galaxy reported by Malesani (GCN Circ. 10621) and not the
afterglow reported by Filgas et al. (GCN Circ. 10617), Updike
et al. (GCN Circ. 10619) and Antonelli et al. (GCN Circ. 10620).
The UVOT position of the source is:

     RA(J2000) =  17:05:26.96  =  256.36278 (deg)
    Dec(J2000) = +11:27:41.9   =  +11.46167 (deg)

with a 90% confidence interval of 0."67.

The 3-sigma upper limits for the finding chart (fc) and
summed exposures from the first and second orbits are reported
below:

FILTER     T_start(s)  T_stop    Exposure     Mag/3UL
========================================================
white fc      87        237        147        20.62+-0.29
white         89       1548        390        20.58+-0.20
white       6143       6343        196        20.32+-0.20
v            628       6754        491        >19.90
b            554       6138        294        20.61+-.44
u            299       7348        697        20.47+-0.41
uvw1         678       7164        491        20.47+-0.42
uvm2         653       6959        491        20.09+-0.32
uvw2         604       6548        308        20.73+-0.54
=======================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.07 (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: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10626
SUBJECT: GRB 100418A: ROVOR optical afterglow detection
DATE:    10/04/19 22:12:24 GMT
FROM:    J. Ward Moody at BYU  <rovor.byu@gmail.com>

 R. Pearson, J. Ward Moody, and C. Pace report for Brigham Young
University's (BYUs) ROVOR team:

Beginning 9.12 hours after the initial Swift detection of GRB 100418A
(GCN 10612), the 16-inch ROVOR telescope observed its optical
afterglow. Twenty-eight 2 minute R band exposures were recorded at
high airmass (2.48) and subsequently averaged together; a combined
frame of 56 minutes was produced.  An optical afterglow was located at
the position specified by Filgas, Klose, and Greiner (GCN 10617).

We report a middle observing time of 06:55:21.474 (9.75 hrs
post-burst) and a R band magnitude of 18.2+/-0.2mag. It was calibrated
using GSC 00984-01465 located at 17:05:55.02+11:27:55.46 (J2000).
Additional follow-up observations are scheduled with ROVOR as well as
BYU's 36-inch telescope on West Mountain Observatory, supported by the
NSF grant AST-0618209.


GRB_name: GRB100418A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10627
SUBJECT: GRB 100418A PAIRITEL NIR Observations
DATE:    10/04/20 02:47:30 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

C. R. Klein, A. N. Morgan, D. A. Perley, and J. S. Bloom (UC Berkeley) report:

We observed the location of the optical afterglow of GRB 100418A
(Marshall et al., GCN 10612) with the 1.3m PAIRITEL located at Mt.
Hopkins, Arizona. Observations began at 2010-04-19 07:51:27 UT, ~10.69
hours after the Swift Trigger, under non-ideal sky conditions, and
continued until clouds obscured the sky.  In  mosaics (effective
exposure time of 0.92 hours) taken simultaneously in the J, H, and Ks
filters, we detect the afterglow (Filgas et al., GCN 10617; Updike et
al., GCN 10619; Antonelli et al., GCN 10620; Pearson et al., GCN
10626).

The preliminary photometry yields:

post burst
t_mid (hr) exp.(hr) filt  mag   m_err
11.13      0.92     J     16.8  0.1
11.13      0.92     H     15.9  0.1
11.13      0.92     Ks    15.3  0.1

We note that our J band point is consistent with little to no fading
since the GROND detection ~3.6 hours prior (using J_AB = J_2mass +
0.90).  This is consistent with the shallow decay implied by the R
band magnitudes in this time period reported thus far (Filgas et al.,
GCN 10617; Updike et al., GCN 10619; Antonelli et al., GCN 10620;
Pearson et al., GCN 10626), and with the the non-fading behavior seen
in the UVOT data (Siegel et al., GCN 10625). Further, the XRT light
curve is roughly flat between ~1000s and ~1 day (see
http://astro.berkeley.edu/~nat/Swift/00419797/xrt/swx00419797.html),
indicating a long optical/X-ray plateau phase.  Continued observations
are encouraged.

Intermittent clouds led to highly variable transmission and sky
brightnesses during the PAIRITEL observations. All magnitudes are
given in the Vega system, calibrated to 2MASS. No correction for
Galactic extinction has been made to the above reported values.


GRB_name: GRB100420A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10628
SUBJECT: GRB 100420A: Swift detection of a burst
DATE:    10/04/20 05:34:36 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
M. M. Chester (PSU), N. Gehrels (NASA/GSFC), C. Guidorzi (U Ferrara),
E. A. Hoversten (PSU), O. M. Littlejohns (U Leicester),
R. Margutti (INAF-OAB), C. B. Markwardt (CRESST/GSFC/UMD),
P. T. O'Brien (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), A. Rowlinson (U Leicester), M. H. Siegel (PSU)
and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:

At 05:22:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100420A (trigger=419932).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 296.127, +55.793 which is 
   RA(J2000) = 19h 44m 31s
   Dec(J2000) = +55d 47' 33"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual for an image trigger, there is nothing of
note in the BAT light curve. 

The XRT began observing the field at 05:24:52.8 UT, 130.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 296.12646, 55.76885 which
is equivalent to:
   RA(J2000)  = 19h 44m 30.35s
   Dec(J2000) = +55d 46' 07.9"
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This
location is 86 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
1.19e+21 cm^-2 (Kalberla et al. 2005). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 134 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 none of
the XRT error circle. 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 0.11. 




Burst Advocate for this burst is W. H. Baumgartner (wayne 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: GRB100420A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10629
SUBJECT: GRB 100420A: ROTSE-III Optical Limits
DATE:    10/04/20 06:05:14 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship@umich.edu>

L. Xiao (Louisiana State), W. Rujopakarn (Steward), B. E. Schaefer
(Louisiana State), T. Guver (U Arizona) and S. B. Pandey (U Mich), report
on behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
100420A (Swift trigger 419932; W. H. Baumgartner et al., GCN 10628),
producing images beginning 8.8 s after the GCN notice time. An automated
response took the first image at 05:24:07.8 UT, 79.8 s after the burst, and
during the gamma-ray emission. We took 10 5-sec, 10 20-sec and 10 60-sec
exposures. These unfiltered images are calibrated relative to USNO A2.0
(R). Imaging is on going.

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. Individual images have limiting
magnitudes ranging from 15.3-16.8; we set the following specific limits.

start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
05:24:07.8 05:25:14.9 67 16.7 79.8 Y
05:25:28.5 05:30:11.0 282 17.3 160.5 Y
05:30:20.3 05:41:42.0 681 17.6 452.3 Y


GRB_name: GRB100418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10630
SUBJECT: GRB 100418A: SMA submm detection
DATE:    10/04/20 06:40:43 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

S. Martin (ESO), G. Petitpas (SMA), A. de Ugarte Postigo (INAF-OAB),
M. Gurwell (SMA), A.J. Castro-Tirado, J. Gorosabel (IAA-CSIC),
D. Garcia-Apaadoo, C. de Breuck, A. Lundgren (ESO) report:

"We have observed the field of GRB 100418A (Marshall et al., GCNC
10612) from SMA in the 345 GHz band starting on April 19th 13:00 UT.
In a preliminary analysis of the data we detect a single source coincident
with the position of the afterglow with a flux density of 20+/-2.4 mJy.

Further observations of this very peculiar source are encouraged."


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10631
SUBJECT: GRB 100418A: VLT optical observations
DATE:    10/04/20 09:21:50 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

Daniele Malesani, Eliana Palazzi, and Simone Scaringi report:

We obtained an R-band image of the afterglow of GRB 100418A (Marshall et 
al., GCN 10612; Filgas et al., GCN 10617) with the X-shooter acquisition 
camera 34.63 hr after the GRB. The afterglow has decayed by 1.11+-0.03 
mag since our previous observation taken 8.37 hr after the GRB 
(Antonelli et al., GCN 10620).

We encourage further observations at all wavelengths of this interesting 
event. We acknowledge support from the ESO staff at Paranal, in 
particular Alvaro Alvarez, Claudia Cid, and Fernando Selman.

[GCN OPS NOTE(20apr10):  Per author's request, Scaringi was added
to the author list.]


GRB_name: GRB100414A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10632
SUBJECT: GRB 100414A: Confirmation of the X-ray afterglow 
DATE:    10/04/20 10:06:01 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page (U. Leicester) and J.K. Cannizzo (NASA/UMBC) report on behalf of the 
Swift-XRT team:

A second Swift-XRT observation of the Fermi-detected GRB 100414A (GCN 
Circs 10594 and 10595) was performed on 2001-04-19, 5.7 days after the 
trigger. The source reported by Page et al. (GCN Circs 10601, 10605) is no 
longer detected, with a 3-sigma upper limit on the count rate of 4.5x10^-3 
count s^-1 (corresponding to an observed flux of 2.5x10^-13 erg cm^-2 
s^-1). This non-detection sets a lower limit on the decay slope of alpha > 
1.5.

With this fading, we can confirm that this source is the X-ray afterglow of GRB 
100414A.

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


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10633
SUBJECT: GRB 100418A: MASTER-Net  optical  observations  
DATE:    10/04/20 10:45:29 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok, O.Gres, O.
Irkutsk State University

V.Yurkov, Yu.Sergienko, D.Varda, A.Garusina Blagoveschensk Educational State 
University, Blagoveschensk


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

A. Tlatov, A.V. Parkhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory


V.Krushinski, I.Zalozhnih, T.Kopytova, A.Popov
Ural State University, Kourovka




MASTER  robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
testing telescope) located at Tunka Valley  (Baykal, Siberia)    was 
responted to the  GRB 100418A (Swift Bat alert, Marshall et al, GCN CIRC 
10612)   21 sec after   Notice time (~ 8 sec delay in internet socket) and 
31 s after the GRB time ( Sun Alt -8 degrees) .

There is now OT on the first 10-s  exposition time unfiltered images 
inside  Swift XRT error box (Pagani et al., GCN CIRC 10622)
brighter 14.5.




The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10634
SUBJECT: GRB 100418A: optical observations
DATE:    10/04/20 15:55:58 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, D. Shakhovkoy (CrAO), A. Pozanenko (IKI)  report on behalf of 
larger GRB  follow-up collaboration:

We observed the field of the Swift GRB 100418A (Marshall  et al. GCN 10612) 
with AZT-11 telescope of CrAO between (UT) Apr. 19  01:26 -- 01:54 under 
poor seeing of about 4 arcsec. The optical afterglow (Marshall  et al. GCN 
10612, Filgas et al. GCN 10617) is clearly detected  in enhanced XRT error 
circle (Osborne et al. GCN 10614). The coordinates of the afterglow are 
(J2000) RA= 17:05:27.08 Dec= +11:27:42.3

The photometry of the afterglow in a stacked image based on USNO-B1.0 star 
1014-0271368  (RA(J2000) = 17:05:26.42 Dec(J2000)= +11:27:32.9)  assuming 
R=17.32  is following:

T0+      Filter,   Exposure, mag.
(mid, d)              (s)

0.1883     R       9x180    18.54 +/-0.03

A finding char can be found at
http://grb.rssi.ru/GRB100418A/GRB100418a_100418_R_azt11.gif 


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10635
SUBJECT: GRB 100418A: RTT150 observations during the optical afterglow maximum
DATE:    10/04/20 18:39:42 GMT
FROM:    Irek Khamitov at TUG  <irekk@tug.tug.tubitak.gov.tr>

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

report:

The optical afterglow of GRB 100418A (Marshall et al., GCN 10612, Filgas 
et al., GCN 10617) was observed with Russian-Turkish 1.5-m telescope
(RTT150,Bakirlitepe, TUBITAK National Observatory, Turkey) in April 18/19
and April 19/20, 2010, in partially cloudy conditions. We obtained a serie 
of 300 sec images in Rc-band in April 18/19, and serie of 600 sec images
in April 19/20.

We found that during April 18 set OT shows strong brightness variations of
Rc ~ 18-20 mag within hour time scale. In the Table below we give our Rc
estimates relative to the nearby USNO-B1.0 star 1014-0271368 (R2Mag=17.32).

April 18
UT (T-T0),h   Rc    err
=================================
21:43 0.5   20.29 +/-0.10
22:38 1.5  >20.50 3-sigma image limit
23:25 2.25  18.64 +/-0.04
23:51 2.6   18.30 +/-0.04
23:58 2.9   18.33 +/-0.02
=================================

April 20
UT (T-T0),h   Rc    err
=================================
00:40 27.5  18.88 +/-0.03

RTT-150 data shows that brightness of OT sharply increased
from 20 to 18 mag at (T-T0) ~ 2 hours. The OT was observed at maximum 
brigtness atapproximately 2.6 hours after the burst and then its flux
started to decline, which is consistent with other measurements 
made later on (Rumyantsev et al., GCN 10634, Filgas et al GCN 10617).

The brightening of the OT is shown in the following RTT150 images:
http://hea.iki.rssi.ru/grb/100418a/indexeng.html

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GRB_name: GRB100420A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10636
SUBJECT: GRB 100420A: SARA Upper Limits
DATE:    10/04/20 20:28:31 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike, Dieter H. Hartmann (Clemson University), and Chris De
Pree (Agnes Scott College) report:

We observed the field of GRB 100420A (Baumgartner et al., GCN 10628) using
the 0.9m SARA telescope located at KPNO beginning 3 hours and 4 minutes
after the BAT trigger.  We obtained 22 minutes of observations in the R
band followed by 20 minutes in the I band at high airmass.  At the
location of the XRT error circle, we detect no new sources down to a
limiting magnitude of R > 19.0, I > 18.5 (as compared to the USNO B1.0
catalog).  No further observations are planned.


GRB_name: GRB100418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10637
SUBJECT: GRB 100418A: SARA second epoch
DATE:    10/04/20 21:07:59 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike, Dieter H. Hartmann (Clemson University), and Chris De
Pree (Agnes Scott College) report:

We re-observed the field of GRB 100418A (Marshall et al., GCN 10612) using
the 0.9m SARA telescope located at KPNO beginning 1.44 days after the
trigger.  Observations consisted of 40 minutes in the R band.  We detect
the afterglow (Filgas et al., GCN 10617) at R = 19.3 +/- 0.1, fading 1.0
mag from our previous detection (upon comparison to USNO B1.0 catalog
field stars).  Further observations are planned.


GRB_name: GRB100420A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10638
SUBJECT: GRB 100420A: Enhanced Swift-XRT position
DATE:    10/04/20 21:25:55 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 1862 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 100420A, 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 = 296.12761, +55.76926 which is equivalent
to:

RA (J2000): 19h 44m 30.63s
Dec (J2000): +55d 46' 09.3"

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) and Evans
et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB100420A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10639
SUBJECT: GRB 100420A: XRT refined analysis
DATE:    10/04/20 22:37:43 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

A. Rowlinson (U Leicester) and W. H. Baumgartner (GSFC/UMBC) report on
behalf of the Swift-XRT team:

We have analysed 6.9 ks of XRT data for GRB 100420A (Baumgartner et al.
GCN Circ. 10628), from 115 s to 13.6 ks after the BAT trigger. The data
comprise 120 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore et
al. (GCN. Circ 10638).

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.69 (+0.47, -0.39), followed by a break at T+721 s to an
alpha of 1.22 (+0.34, -4.02).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.83 (+0.22, -0.20). The
best-fitting absorption column is consistent with the Galactic value of
1.2 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 4.2 x 10^-11 (5.3 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
1.22, the count rate at T+24 hours will be 2.3 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.7 x
10^-15 (1.2 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00419932.

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


GRB_name: GRB100420A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10640
SUBJECT: GRB 100420A: Swift/UVOT Upper Limits
DATE:    10/04/21 04:21:50 GMT
FROM:    Margaret Chester at PSU  <chester@astro.psu.edu>

M. M. Chester (PSU) and W. H. Baumgartner (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100420A
134 s after the BAT trigger (Baumgartner et al., GCN Circ. 10628).
No optical afterglow consistent with the enhanced XRT position  
(Beardmore
et al., GCN Circ. 10638) is detected in the initial UVOT exposures.
Preliminary 3-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           134          284          147         >20.8
u_FC               292          542          246         >20.0
white              134        13589         1503         >22.7
v                  624        30201         1434         >20.5
b                  548        19368         1911         >22.2
u                  292        18659         2409         >21.7
w1                 674        17744         1435         >21.6
m2                 648        30928         1260         >21.5
w2                 598        29287         1434         >21.4

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: GRB100414A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10641
SUBJECT: GRB 100414A: CFHT optical observations
DATE:    10/04/21 10:17:20 GMT
FROM:    Yuji Urata at Nat. Central U.  <urata@astro.ncu.edu.tw>

Y. Urata (NCU) and K.Y Huang (ASIAA) on behalf of EAFON report;

"We observed the location of the GRB100414A optical afterglow
(Cucchiara et al. 10608) with CFHT on the night of April 19 (5.2 day
after the trigger) and 20 (6.2 day). The g', r' and i' band images
show the afterglow clearly. We estimate preliminary magnitudes of
r'=22.46+/-0.05 (5.19 day) and r'=22.84+/-0.05 (6.17 day) against the
SDSS field stars. Combined with the photometric results reported by
Filgas et al (10607) and Cucchiara (10606), the optical afterglow
light curves are well described by a simple power law decay with the
temporal index about 2.5."


GRB_name: GRB100420A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10642
SUBJECT: GRB100420A: MITSuME optical upper limits
DATE:    10/04/21 10:21:51 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>

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

We observed the field of GRB 100420A (Baumgartner et al. GCN 10628)
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 2010-04-20 18:03:04 UT (~12.7h after the
burst). We did not find any new point source in the Enhanced XRT
error circle (Beardmore et al., GCNC 10638) in all the three bands.

Three sigma upper limits of the OT are listed below. We used GSC2.3
catalog for flux calibration.


T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.53748   18:16:41   1320.0      >18.7  >18.6  >18.3
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10643
SUBJECT: GRB 100418A: RTT150 optical observations
DATE:    10/04/21 15:06:43 GMT
FROM:    Irek Khamitov at TUG  <irekk@tug.tug.tubitak.gov.tr>

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

report:

The optical afterglow of GRB 100418A (Marshall  et al., GCN 10612, Filgas 
et al., GCN 10617) was observed with Russian-Turkish 1.5-m telescope 
(RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) in April 20/21, 2010,
at moderate seeing conditions.

We obtained a serie of 600 sec and 300 sec images in Rc-band.

The Table gives our Rc value estimation relative nearby USNO-B1.0
star 1014-0271368  (R2Mag=17.32).

April 21, 2010

  UT    (T-T0), h    Rc       err
=================================
00:48  51.6     20.05   +/-0.03


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GRB_name: GRB100418A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10644
SUBJECT: GRB 100418A: further GROND observations and light curve fit
DATE:    10/04/21 19:20:41 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose@tls-tautenburg.de>

R. Filgas (MPE Garching), D. A. Kann, S. Klose (all Tautenburg),
M. Nardini, and J. Greiner (all MPE Garching), report on behalf of the GROND 
team:

GROND on La Silla (Greiner et al. 2008, PASP 120, 405)  continues 
observing the afterglow of GRB 100418A.  GROND data, with the first epoch 
at 28 ks after the burst and the last data point at 133 ks after the 
burst, in combination with data from Updike et al. (GCN 10619), Antonelli 
et al. (GCN 10620), Malesani (GCN 10621), Pearson et al. (GCN 10626), 
Malesani et al. (GCN 10631), Rumyantsev et al. (GCN 10634), Bikmaev et al. 
(GCN 10635), Updike et al. (GCN 10637), and Bikmaev et al. (GCN 10643), 
show that the R-band afterglow light curve had a break at t = 1.11 +/- 
0.01 days and is now decaying with a slope of 2.41 +/- 0.08.

While the steep decay of the afterglow is in favor of a SN search, the 
bright host (Malesani, GCN 10621) might make a detection difficult. 
Assuming a SN 1998bw template, a Galactic visual extinction along the line 
of sight of 0.2 mag, no GRB host extinction but 0.2 mag host extinction 
for SN 1998bw, we predict the following SN peak times and magnitudes:

      band         dt/days         mag
      V            21.5           24.5
      R            22.5           23.7
      I            24.0           22.9
      J            29.5           22.8

This message can be cited.


GRB_name: GRB100418A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10645
SUBJECT: GRB 100418A: Continuing Swift/UVOT Observations
DATE:    10/04/21 19:26:57 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU), F. E. Marshall (NASA/GSFC), S. T. Holland
(NASA/GSFC), M. M. Chester (PSU), M. de Pasquale (MSS-UCL) and
S. R. Oates (MSSL-UCL) report on behalf of the Swift/UVOT team.

Ongoing Swift/UVOT observations of the field of GRB 100418A
(Marshall et al., GCN Circ. 10612) have continued to monitor the
behavior of the optical transient.  UVOT photometry taken about
50 ks after the burst shows an increase in brightness of about a
magnitude compared to the initial detection, confirming the late
increase in brightness reported by Bikamev et al. (GCN Circ. 10635).
The OT has since decayed from this peak with a decay rate of -1.0+-0.1
in the UVOT white filter. This decay is slightly shallower than the
decay observed by Malesani et al. (GCN Circ. 10631, 10643), Updike et
al. (GCN Circ. 10637) and Filgas et al. (GCN Circ 10644).  Such a late
peak in brightness is very unusual and Swift will continue to monitor
the GRB.

Photometry from the summed exposures is reported below:

FILTER     T_start(s)  T_stop    Exposure        Mag
=========================================================
white fc      88        237        147        20.62+-0.29
white         88       1548        390        20.58+-0.20
white       6143       6343        196        20.32+-0.20
white      50996      52990       1959        19.38+-0.03
white      86204      92193       2308        19.77+-0.04
white     149282     156466       3812        20.54+-0.06
=========================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.07 (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: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10646
SUBJECT: GRB100418A: REM possible afterglow detection
DATE:    10/04/21 19:36:39 GMT
FROM:    Stefano Covino at Brera Astronomical Observatory  <stefano.covino@gmail.com>

S. Covino (INAF/Brera), D. Fugazza (INAF/Brera), L.A. Antonelli (INAF/Roma), D. Malesani (DARK/NBI), on behalf of the REM team report:

The robotic 60-cm REM telescope located at La Silla (Chile) observed automatically the field of GRB 100418A (GCN 10612, Marshall et al.) from April 19 3:25 UT to 4:34 UT (about 6.2 to 7.4 hr from the burst) in the optical and in the near-infrared.

Nothing is visible at the position of the optical counterpart reported by GROND (GCN 10617, Filgas et al.) except for a single H-band frame with mean time 4:14 UT (about 6.9 hr after the burst) and 5 min exposure. During this observation the afterglow is clearly detected at H=14.3 +- 0.2. The 3sigma upper limits in other H-band frames obtained always with 5 min exposure is H>15.2.

This rapid variability resembles the one observed by Bikmaev et al. (GCN 10635) with the RTT150 which, however, observed the field several hours before. Given this very unusual behavior, we encourage inspection of other datasets taken at comparable epochs.


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10647
SUBJECT: GRB 100418A: WSRT Radio Detection
DATE:    10/04/21 23:39:12 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU), A.P. Kamble, R.A.M.J. Wijers,
E. Rol (U of Amsterdam), C. Kouveliotou (NASA/MSFC) and K. Wiersema
(U of Leicester) report on behalf of a large collaboration:

"We observed the position of the GRB 100418A afterglow with the
Westerbork Synthesis Radio Telescope at 4.8 GHz at April 20 20.74 UT
to April 21 8.71 UT, i.e. 1.98 - 2.48 days after the burst (GCN 10612).
We detect a radio source with a flux density of 369 +/- 29 microJy
at the position of the optical counterpart (GCN 10616).

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


GRB_name: GRB100418A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10648
SUBJECT: GRB 100418A: Continued PAIRITEL NIR Observations
DATE:    10/04/22 12:36:14 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

A. N. Morgan, D. A. Perley, C. R. Klein, and J. S. Bloom (UC Berkeley) report:

We continued to observe the location of the optical afterglow of GRB
100418A (Marshall et al., GCN 10612) with the 1.3m PAIRITEL located at
Mt. Hopkins, Arizona for a second epoch beginning at 2010-04-20 07:59
UT, ~34.8 hours after the Swift trigger.  In  mosaics (effective
exposure time of 1.27 hours) taken simultaneously in the J, H, and Ks
filters, we observe that the afterglow has faded approximately 1
magnitude since our first epoch (Klein et al., GCN 10627).
Unfortunately, poor weather conditions prevented further observations
on 2010-04-21 and 2010-04-22.

The preliminary photometry yields:

post burst
t_mid (hr) exp.(hr) filt  mag   m_err
35.81      1.27     J     18.0  0.1
35.81      1.27     H     17.2  0.1
35.81      1.27     Ks    16.3  0.1

All magnitudes are given in the Vega system, calibrated to 2MASS. No
correction for Galactic extinction has been made to the above reported
values.


GRB_name: GRB100414A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10649
SUBJECT: GRB 100414A:  Radio Afterglow Detection with the Expanded VLA
DATE:    10/04/22 17:44:55 GMT
FROM:    Poonam Chandra at Royal Mil. College Canada  <Poonam.Chandra@rmc.ca>

Poonam Chandra (RMC), Dale A. Frail (NRAO), S. Bradley Cenko (Berkeley)
and Fiona Harrison (Caltech) report on behalf of a larger collaboration:

We used the Expanded Very Large Array (EVLA) to observe the
Fermi burst GRB 100414A (Takahashi et al, GCN 10594 Foley GCN 10595)
on 2010 Apr 19 UT Within the revised XRT error circle (Goad et al
GCN 10605).

We detect the GRB afterglow with a flux density of 406 +/- 22 uJy.


The EVLA is undergoing active commissioning and as such these results
should be considered preliminary=2E 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.

[GCN OPS NOTE(22apr10):  Per author's request, the "13A" in the 
Subject line was changed to "14A".]


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10650
SUBJECT: Radio afterglow detection of GRB 100418A with the EVLA
DATE:    10/04/22 17:47:34 GMT
FROM:    Poonam Chandra at Royal Mil. College Canada  <Poonam.Chandra@rmc.ca>

Poonam Chandra (RMC) and Dale A. Frail (NRAO)
report on behalf of a larger collaboration:

We used the Expanded Very Large Array (EVLA) to observe the Swift GRB
100418A (Marshall et al., GCN 10612) on 2010 Apr 21 UT.

We detect the GRB afterglow with a flux density of 458 +/- 20 uJy
at the GROND optical afterglow position (Filgas et al, GCN 10617).

The EVLA is undergoing active commissioning and as such these results
should be considered preliminary. 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: GRB100423A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10651
SUBJECT: GRB 100423A: Swift detection of a burst
DATE:    10/04/23 00:48:05 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

M. C. Stroh (PSU), P. A. Evans (U Leicester), J. M. Gelbord (PSU),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL),
M. H. Siegel (PSU), M. A. Stark (PSU) and L. Vetere (PSU) report on
behalf of the Swift Team:

At 00:34:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100423A (trigger=420247).  Swift could not slew to
this source because it was too close to the Moon (~10 degrees). 
The BAT on-board calculated location is 
RA, Dec 136.477, +21.479 which is 
   RA(J2000) = 09h 05m 54s
   Dec(J2000) = +21d 28' 46"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed single peak
FRED with a duration of at least 100 sec, and a brief precursor spike
at T-0.5.  The peak count rate was ~21000 counts/sec (15-350 keV), 
at ~0 sec after the trigger. 

Due to a Moon constraint, Swift could not slew to observe this
source with the XRT and UVOT.  The source will become observable
early on April 24 UT. 

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: GRB100423A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10652
SUBJECT: GRB 100423A: GROND discovery of afterglow
DATE:    10/04/23 01:42:03 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

Robert Filgas, Jochen Greiner (both MPE) and Adria Updike (Clemson Univ.)
report on behalf of the GROND team:

We observed the field of GRB 100423A (Swift trigger 420247; Stroh et al., 
GCN 10651) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, 
PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory 
(Chile). Observations started at 00:37 UT on April 23, 2010, 150 sec after the
Swift trigger. They were performed at an average seeing of 1" and at airmass
of 1.8, respectively.

We found a single variable point source within the 3' error circle, not
visible in either 2MASS or DSS2 at 

RA  (J2000) =  09h 05m 50.22s
Dec (J2000) = +21d 29' 54.3"

with an uncertainty of 0.3" in each coordinate. From the first 4 min
observation we estimate the following preliminary magnitudes 
g = 17.7+-0.1
r = 17.6+-0.1
i = 17.5+-0.1
z = 17.4+-0.1
J = 17.3+-0.1
H = 16.9+-0.1
K = 16.5+-0.1

calibrated against SDSS and 2MASS, and not corrected for the expected
foreground extinction of E(B-V)=0.04 (Schlegel et al. 1998).

The object faded by 0.3 mag between the first and second 4 min observation,
and thus is likely the GRB afterglow.

Since the object is seen in all GROND bands, the redshift is smaller than 
about 3.5. We encourage spectroscopic observations.


GRB_name: GRB100423A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10653
SUBJECT: GRB 100423A: Skynet/PROMPT Detections 
DATE:    10/04/23 02:24:15 GMT
FROM:    Daniel E. Reichart at U.North Carolina  <reichart@physics.unc.edu>

K. Ivarsen, D. Reichart, J. Haislip, A. LaCluyze, R. Egger, A. Foster, J. 
Moore, A. Oza, M. Schubel, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Swift/BAT localization of GRB 100423A (Stroh et al., 
GCN 10651) with four of the 16" PROMPT telescopes at CTIO beginning 49 
seconds after the trigger in BVRI.

We detect the afterglow (Filgas et al., GCN 10652) in all filters.

At 51 seconds after the trigger, its magnitude is R = 15.81 +0.12 -0.11 
(calibrated to 13 SDSS stars, transformed using Jester et al., 2005, ApJ, 
130, 873.)

Until about 8 minutes after the trigger, the afterglow faded with a 
power-law index of about -0.5.  Afterward, it steepened.  Between 30 and 90 
minutes after the trigger, the afterglow faded with a power-law index of 
about -1.1.

Skynet's most recent BVRI light curve, calibrated to SDSS stars, can be 
found here:

http://skynet.unc.edu/grb/grb100423a.png


GRB_name: GRB100423A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10658
SUBJECT: GRB 100423A: Swift-BAT refined analysis
DATE:    10/04/23 11:45:41 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),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU),
M. C. Stroh (PSU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 100423A (trigger #420247)
(Stroh, et al., GCN Circ. 10651).  The BAT ground-calculated position is
RA, Dec = 136.471, 21.487 deg, which is 
   RA(J2000)  =  09h 05m 53.0s 
   Dec(J2000) = +21d 29' 13.4" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 74%.
 
The mask-weighted light curve shows a couple small peaks starting at ~T-4 sec,
then a large peak at T_zero and peaking at ~T+0.1 sec, and then a long roughly
exponential decay out to T+160 where the burst went out of the BAT FOV
due a slew to avoid an observing constraint.  We cannot quote a T90,
because there was still burst emission when it went out of the FOV.
 
The time-averaged spectrum from T-12.9 to T+99.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.07 +- 0.05.  The fluence in the 15-150 keV band is 8.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+10.60 sec in the 15-150 keV band
is 1.2 +- 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/420247/BA/


GRB_name: GRB100423B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10659
SUBJECT: GRB 100423B: Fermi GBM detection
DATE:    10/04/23 12:48:10 GMT
FROM:    David Gruber at MPE  <dgruber@mpe.mpg.de>

David Gruber (MPE)  
reports on behalf of the Fermi GBM Team: 

"At 05:51:25.75 UT on 23 April 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100423B (trigger 293694687 / 100423244).

The on-ground calculated location, using the GBM trigger 
data, is RA = 119.7, DEC = 5.8 (J2000 degrees, 
equivalent to 07h 58m, 05d 46'), with an uncertainty 
of 1.5 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 40 degrees.

The GBM light curve consists of one pulse
with a duration (T90) of about 21.6 +/- 1.1 s (8-1000 keV). 
The time-averaged spectrum from T0-2.0 s to T0+23.6s is 
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.84 +/-0.05 and
the cutoff energy, parameterized as Epeak, is 1034 (+144/-117) keV
(CSTAT 1395.6 for 845 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(1.226 +/- 0.019)E-5 erg/cm^2. The 1.024-sec peak photon flux measured 
starting from T0+5.3 s in the 8-1000 keV band 
is 3.53 +/- 0.13 ph/s/cm^2.

A Band function fits the spectrum equally well (CSTAT 1394.3 for 844 d.o.f.) 
with Epeak= 1006 (+122/-113) keV, alpha = -0.83 (+0.05/-0.04) 
and beta = -3.15 (+0.45/-1.24). 

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


GRB_name: GRB100420A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10660
SUBJECT: GRB 100420A: Swift-BAT refined analysis
DATE:    10/04/23 17:31:00 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),
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),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-205 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 100420A (trigger #419932)
(Baumgartner, et al., GCN Circ. 10628).  The BAT ground-calculated position is
RA, Dec = 296.090, 55.755 deg, which is 
   RA(J2000)  =  19h 44m 21.5s 
   Dec(J2000) = +55d 45' 18.7" 
with an uncertainty of 4.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.
 
The mask-weighted light curve shows a single peak starting around T-10 sec,
peaking at ~T+10 sec, and ending at ~T+60 sec.  T90 (15-350 keV) is
48 +- 36 sec (estimated error including systematics).
 
The time-averaged spectrum from T-30 to T+70 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.17 +- 0.22.  The fluence in the 15-150 keV band is 5.7 +- 1.0 x 10^-7 erg/cm2.
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/419932/BA/


GRB_name: GRB100418A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10661
SUBJECT: GRB 100418A: Possible Evidence for a Supernova 
DATE:    10/04/23 19:18:34 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/USRA/GSFC), F. E. Marshall (NASA/GSFC),
M. Page (MSSL-UCL), M. de Pasquale (MSSL-UCL), and
M. H. Siegel (PSU) report on behalf of the Swift/UVOT team:

     Swift/UVOT white photometry of GRB 100418A reveals a light curve
with a rise and decay that are broadly similar to the white light
curve of GRB 060218/SN2006aj.  The UVOT spectral energy distribution
at 6400 s is consistent with a power law with a spectral index of beta
= 0.2 (f = nu^-beta), which is similar to the UVOT spectral energy
distribution for GRB 060218/SN2006aj at 9300 s.  In addition, the
X-ray light curve of GRB 100418A is broadly similar to the X-ray light
curves of GRB 100316D and GRB 060218, both of which had supernova
components.  Therefore, we suggest that the brightening of the
afterglow of GRB 100418A seen at approximately 10,000 s (Bikamev et
al. 2010, GCNC 10635; Siegel et al. 2010, GCNC 10645) may be the shock
breakout from a supernova associated with this burst.  If this is the
case, and the supernova is similar to SN1998bw, then the supernova has
not yet reached maximum light.  Ground based observations to determine
if a supernova is present are encouraged.


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10664
SUBJECT: GRB 100418A: ROVOR optical measurements at 35 hours
DATE:    10/04/23 23:12:34 GMT
FROM:    J. Ward Moody at BYU  <rovor.byu@gmail.com>

J. W. Moody, D. Laney, R. Pearson, and C. Pace report for the BYU ROVOR team:
Beginning 35 hours after the initial detection of GRB 100418A we
obtained BVR optical data using the BYU WMO 0.9m telescope.
Preliminary magnitudes were found by referencing against USNO-B1.0
star 1014-0271368 (RA(J2000) = 17:05:26.42, Dec(J2000) = +11:27:32.9).
 Assuming B=18.66, V=18.00 and R=17.32 we obtain the following values:

post burst
t_mid(hr)   exp.(min)  filter  mag.  error
37.18        25
35.91
35.25


Poor weather prevented observations on 2010-04-21 and 2010-04-22


GRB_name: GRB100418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10665
SUBJECT: GRB 100418A: ROVOR optical measurements at 35 hours
DATE:    10/04/23 23:41:42 GMT
FROM:    J. Ward Moody at BYU  <rovor.byu@gmail.com>

J. W. Moody, D. Laney, R. Pearson, and C. Pace report for the BYU ROVOR team:

Beginning approximately 35 hours after the initial detection of GRB 100418A we
obtained BVR optical data using the BYU WMO 0.9m telescope.
Preliminary magnitudes were found by referencing against USNO-B1.0
star 1014-0271368 (RA(J2000) = 17:05:26.42, Dec(J2000) = +11:27:32.9).
Assuming its values are B=18.66, R=17.32 (from catalog) and V=18.0
(our estimate) we obtain the following values:

post burst
t_mid(hr)   exp.(min)  filter  mag.  error
37.18        25            B      19.9  0.15
35.91        25            V      19.3  0.1
35.25        20            R      18.5  0.1


Poor weather has prevented subsequent observations.


GRB_name: GRB100420A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10666
SUBJECT: GRB 100420A: GRT Optical Observation
DATE:    10/04/24 01:26:57 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),
T. Okajima (JHU/GSFC), Y. Urata (NCU), C.A. Wallace (FGCU)

We observed the field of GRB 100420A detected by Swift
(trigger #419932; Baumgartner et al., GCN Circ. 10628) with the 14-inch
Goddard Robotic Telescope (GRT) located at the Goddard Geophysical
and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/).

Total 435 images of 5 sec (200 images), 30 sec (80 images), 
60 sec (120 images) and 100 sec (35 images) exposures were taken in 
the R filter starting from April 20 05:26:53 (UT) about 4.2 minutes after 
the trigger and stopped on April 20 09:49:15 (UT).  We do not detect 
the optical afterglow both in the individual images and the stucked 
image, which only combined good quality 400 images, inside the XRT 
position (Rowlinson et al., GCN #10639).  The estimated three sigma 
upper limit of the combined image (total exposure of 10600 sec) is ~18.9  
mag using the USNO-B1 catalog. 


GRB_name: GRB100424A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10667
SUBJECT: GRB 100424A: Swift detection of a burst
DATE:    10/04/24 16:45:28 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

E. A. Hoversten (PSU), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
W.B Landsman (GSFC), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
C. Pagani (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU) and
M. A. Stark (PSU) report on behalf of the Swift Team:

At 16:32:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100424A (trigger=420367).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 209.453, +1.513 which is 
   RA(J2000)  =  13h 57m 49s
   Dec(J2000) = +01d 30' 48"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT lightcurve shows nothing as is usual
for an image trigger. 

The XRT began observing the field at 16:34:42.1 UT, 119.8 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 209.4467, +1.5366 which is equivalent to:
   RA(J2000)  = 13h 57m 47.20s
   Dec(J2000) = +01d 32' 11.7"
with an uncertainty of 5.1 arcseconds (radius, 90% containment). 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 2.09e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 128 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
0.03. 

Burst Advocate for this burst is E. A. Hoversten (hoversten 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.)


