# GCN_circulars

GRB_name: GRB181020A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23360
SUBJECT: GRB 181020A: Swift/UVOT Detection
DATE:    18/10/21 18:39:11 GMT
FROM:    Jeffrey Gropp at PSU  <jdg44@psu.edu>

J. D. Gropp (PSU), M. De Pasquale
(U. Instanbul) and Moss (George Washington University)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181020A
122 s after the BAT trigger (Moss et al., GCN Circ. 23349).
A fading source consistent with the XRT enhanced position
(Goad et al. GCN Circ. 23351)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  00:55:55.77 =  13.98239 (deg.)
    Dec (J2000) = -47:22:51.9  = -47.38108 (deg.)
with an estimated uncertainty of 0.45 arc sec. (radius, 90% confidence).
This optical afterglow is also reported by VLT/X-shooter, Fynbo et al., GCN
Circ. 23356;
LCO Cerro Tololo, Cucchiara et al., GCN Circ. 23358;  and its position is
consistent
with the Fermi LAT Measurement reported in, Axelsson et al., GCN Circ.
23350;

Preliminary detections and 3-sigma upper limits using the UVOT photometric
system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are:

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

b                     352             1027             97
17.18+-0.07
m2                  427               745             58      >18.06
u_fc                 96               6797           768
18.52+-0.09
u                      96                346            245
17.60+-0.08
v                      21                 720              67
 14.89+-0.04
w1                  452                 769              58       >18.20
w2                  379                1053             97       >18.56

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).

We note that the non-detection in the UV filters is expected for a source
at the reported
redshift z=2.94 (VLT/X-shooter, Fynbo et al., GCN Circ. 23356;), given
the Lyman forest absorption by intergalactic hydrogen.


GRB_name: GRB181020A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23362
SUBJECT: GRB 181020A: REM detection
DATE:    18/10/22 12:16:45 GMT
FROM:    Andrea Melandri at INAF-OAB  <andrea.melandri@brera.inaf.it>

A. Melandri, S.Covino, P. D'Avanzo, D. Fugazza (INAF-OAB), on behalf of the REM team, report:

We observed the optical counterpart of GRB 181020A (Moss et al. GCN 23349; Axelsson GCN 23350; Veres GCN 23352; Fynbo et al. GCN 23356; Cucchiara et al. GCN 23358; Gropp et al. GCN 23360) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile). The observations were performed starting on 2018 October 20 at 23:51 UT (i.e. 4.86 hrs after the burst) and were carried in the g, r, i, z, J, H and K bands. 

The GRB afterglow is detected in the first set of optical and NIR images. From preliminary photometry we estimate the following magnitudes:

r = 17.3 +/- 0.2 
i = 16.8 +/- 0.1 

at a mean time of 294 min from the GRB time (AB magnitudes, calibrated against the USNO UCAC4 catalogue).


GRB_name: GRB181020A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23363
SUBJECT: Konus-Wind observation of GRB 181020A
DATE:    18/10/22 14:49:57 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The  GRB 181020A  (Swift-BAT detection:
Moss et al., GCN 23349; Sakamoto  et al., GCN 23357;
Fermi-LAT detection: Axelsson, GCN 23350;
Fermi GBM detection: Veres, GCN 23352)
triggered Konus-Wind at T0=68437.284 s UT (19:00:37.284).

The burst light curve shows a single pulse with a total duration of ~26 s.
The emission is seen up to ~5 MeV.

As observed by Konus-Wind, the burst
had a fluence of 4.17(-0.54,+0.58)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+7.552 s,
of 8.27(-1.99,+2.05)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+15.360 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.73(-0.11,+0.13),
the high energy photon index beta = -2.35(-0.41,+0.22),
the peak energy Ep = 371(-52,+57) keV,
chi2 = 80/97 dof.

Assuming the redshift z=2.938 (Fynbo et al., GCN 23356)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is 8.28(-1.07,+1.16)x10^53 erg,
the peak luminosity L_iso is 6.47(-1.56,+1.60)x10^53 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is 1461(-205,+225) keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181020_T68437/

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


GRB_name: GRB181022A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23364
SUBJECT: GRB 181022A: Swift detection of a burst
DATE:    18/10/22 17:53:32 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), J.D. Gropp (PSU), J. A. Kennea (PSU),
H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU),
M. J. Moss (George Washington University), K. L. Page (U Leicester),
D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 17:30:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181022A (trigger=868312).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 56.795, -29.332, which is 
   RA(J2000)  =  03h 47m 11s
   Dec(J2000) = -29d 19' 55"
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 10 sec.  The peak count rate
was ~800 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 17:31:49.9 UT, 96.8 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 56.7920,
-29.3797 which is equivalent to:
   RA(J2000)  = 03h 47m 10.09s
   Dec(J2000) = -29d 22' 46.8"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 171 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 (8.80 x
10^19 cm^-2, Willingale et al. 2013), with an excess column of 4.1
(+3.17/-2.70) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting 97
seconds after the BAT trigger. No credible afterglow candidate has been found
in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT
error circle. 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 0.01. 

This source lies within the current (Sector 4) field-of-view of TESS camera 2. 

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: GRB181022A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23365
SUBJECT: GRB 181022A: Swift-BAT refined analysis
DATE:    18/10/23 02:14:38 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+876 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 181022A (trigger #868312)
(Marshall et al., GCN Circ. 23364).  The BAT ground-calculated position is
RA, Dec = 56.808, -29.374 deg which is
   RA(J2000)  =  03h 47m 13.9s
   Dec(J2000) = -29d 22' 26.5"
with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a weak pulse that starts at ~T-2 s
and ends at ~T+6 s. T90 (15-350 keV) is 6.74 +- 2.30 sec (estimated error
including systematics).

The time-averaged spectrum from T-1.65 to T+5.65 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.78 +- 0.41.  The fluence in the 15-150 keV band is 1.9 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+4.40 sec in the 15-150 keV band
is 0.4 +- 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/868312/BA/


GRB_name: GRB181023A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23366
SUBJECT: GRB 181023A: Swift detection of a burst
DATE:    18/10/23 02:21:45 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>

F. E. Marshall (NASA/GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC),
J. A. Kennea (PSU), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC),
M. J. Moss (George Washington University) and D. M. Palmer (LANL)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 02:04:02 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181023A (trigger=868427).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 248.329, +19.564 which is 
   RA(J2000) = 16h 33m 19s
   Dec(J2000) = +19d 33' 51"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual with an image trigger, the available
BAT light curve shows no significant structure. 

The XRT began observing the field at 02:07:17.8 UT, 195.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 248.32979, 19.57140 which is equivalent
to:
   RA(J2000)  = 16h 33m 19.15s
   Dec(J2000) = +19d 34' 17.0"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 26 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 (6.04 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.4
(+2.82/-2.40) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 199 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
0.05. 

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: GRB181022A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23367
SUBJECT: GRB 181022A: Swift/UVOT Upper Limits
DATE:    18/10/23 03:30:07 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 181022A: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181022A
78 s after the BAT trigger (Marshall et al., GCN Circ. 23364).
No optical afterglow consistent with the XRT position
(Marshall et al. GCN Circ. 23364)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

u_FC                98          347          246         >20.5
v                   78         4922          288         >19.8
u                   98         5429          503         >20.4
w1                 661         5332          274         >20.1
m2                4927         5127          197         >20.2
w2                 356         4717          442         >20.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181023A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23368
SUBJECT: GRB 181023A: KAIT Optical Upper Limit
DATE:    18/10/23 04:24:34 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

Xuhui Han (NAOC), WeiKang Zheng (UC Berkeley) and Alexei V. Filippenko
(UC Berkeley) report on behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 181023A (Marshall et al.,
GCN 23366) starting at 02:16:07 UT, ~12 minutes after the burst
under dusk twilight condition. Observations were performed in the
clear (roughly R) filters, and the exposure time was 60s per image.
Observations lasted for about 25 minutes before it set beyond KAIT
hour agnle limit. We do not detect any optical afterglow candidate
within the XRT position error circle (Marshall et al., GCN 23366)
neither in single image, nor in the co-add images. The typical
limiting magnitude of our single clear image is about 19.0 mag
calibrated to the Pan-STARRS1 catalog.


GRB_name: GRB181023A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23369
SUBJECT: GRB 181023A: Enhanced Swift-XRT position
DATE:    18/10/23 04:59:08 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1424 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 181023A, 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 = 248.32870, +19.57062 which is equivalent
to:

RA (J2000): 16h 33m 18.89s
Dec (J2000): +19d 34' 14.2"

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: GRB181022A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23370
SUBJECT: GRB 181022A: LCO Sutherland observations
DATE:    18/10/23 10:10:06 GMT
FROM:    Renato Martone at Universita' di Ferrara  <mrtrnt@unife.it>

R. Martone, C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

We observed Swift GRB 181022A (Marshall et al., GCN Circ. 23364) with the LCO 1-m unit at Sutherland on October 22, from 22:20 to 22:51 UT (about 5 hours from the GRB trigger time) with the SDSS i' filter. Within the enhanced Swift-XRT error circle (Marshall et al. GCN Circ. 23364) we do not detect any source down to iâ€™>19.0 mag from a 10x120s exposure at a mid time of about 5.05 hours after the GRB trigger time, as calibrated against nearby USNOB1 objects.


GRB_name: GRB181022A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23371
SUBJECT: GRB 181022A: GROND upper limits
DATE:    18/10/23 12:07:26 GMT
FROM:    Patricia Schady at Swift  <p.schady@bath.ac.uk>

P. Schady (Univ. of Bath) and J. Bolmer (MPE, Garching) report:


We observed the field of GRB 181022A (Swift trigger 868312; Marshall et al., GCN #23364) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).


Observations started at 01:53 UT on 2018-10-23, 8.4 hrs after the GRB trigger. They were performed at an average seeing of 1.4" and average airmass of 1.8.


Based on a total of 16 mins integration time, we do not detect a source within the Swift-XRT error circle reported by Marshall et al. (GCN #868312) down to the following 3 sigma AB magnitudes:


g' > 22.8 mag

r' > 22.9 mag

i' > 22.7 mag

z' > 22.5 mag

J > 21.3 mag

H > 20.8 mag

K > 18.9 mag


The given limits are derived based on calibrating the images against GROND zeropoints and 2MASS field stars and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.01 in the direction of the burst (Schlafly & Finkbeiner 2011).


We thank Markus Rabus for the excellend support from La Silla.


GRB_name: GRB181022A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23372
SUBJECT: GRB 181022A: MITSuME Akeno optical upper limits
DATE:    18/10/23 15:22:37 GMT
FROM:    Yutaro Tachibana at Tokyo Tech  <tachibana@hp.phys.titech.ac.jp>

K. Iida, Y. Tachibana, R. Itoh, K. L. Murata, S. Harita, K. Morita,
K. Shiraishi, M. Niwano, R. Adachi, M. Oeda,
Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 181022A
(F. E. Marshall et al., GCN Circular #23364)
with the optical three color (g', Rc, and Ic) CCD cameras attached to
the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 2018-09-05 17:32:02.95 UT.
We did not find any point source at the enhanced position of the
XRT error circle (F. E. Marshall et al., GCN Circular #23364) in all three
bands.
We obtained following 3-sigma upper limits for the magnitudes.

T0+[min]    MID-UT      T-EXP[sec]    g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
109.95     18:29:22  420   >18.4   >18.2   >17.7
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC catalog for flux calibration.


GRB_name: GRB181023A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23373
SUBJECT: GRB 181023A: Swift-XRT refined Analysis
DATE:    18/10/23 15:40:45 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), A.P.
Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester) and F.E. Marshall report on behalf of the Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 181023A (Marshall et al. GCN
Circ. 23366), from 214 s to 36.1 ks after the  BAT trigger. The data
comprise 493 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. 23369).

The late-time light curve (from T0+5.4 ks) can be modelled with a
series of power-law decays. The initial decay index is alpha=1.56
(+0.16, -0.18). At T+12.4 ks  the decay steepens to an alpha of 3.9
(+2.1, -0.4). The light curve breaks again at T+18.1 ks to a decay with
alpha=-1.5 (+0.0, -0.7),  before a final break at T+22.9 ks s after
which the decay index is 2.9 (+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 1.79 (+/-0.08). The
best-fitting absorption column is  2.3 (+/-0.3) x 10^21 cm^-2, in
excess of the Galactic value of 6.0 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.1 x 10^-11 (5.2 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.3 (+/-0.3) x 10^21 cm^-2
Galactic foreground: 6.0 x 10^20 cm^-2
Excess significance: 9.0 sigma
Photon index:      1.79 (+/-0.08)

If the light curve continues to decay with a power-law decay index of
2.9, the count rate at T+24 hours will be 4.5 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x
10^-13 (2.4 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/00868427.

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


GRB_name: GRB181022A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23374
SUBJECT: GRB 181022A: Swift-XRT refined Analysis
DATE:    18/10/23 17:54:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Tohuvavohu (PSU), S.
J. LaPorte (PSU), J.A. Kennea (PSU), P.A. Evans (U. Leicester), J.P.
Osborne (U. Leicester), K.L. Page (U. Leicester), V. D'Elia (ASDC) and
F.E. Marshall report on behalf of the Swift-XRT team:

We have analysed 2.0 ks of XRT data for GRB 181022A (Marshall et al.
GCN Circ. 23364), from 106 s to 5.4 ks after the  BAT trigger. The data
are entirely in Photon Counting (PC) mode. The best available XRT
position  (using the promptly downlinked event data, the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue) is
RA, Dec = 56.7920, -29.3798 which is equivalent to:

RA (J2000): 03 47 10.09
Dec(J2000): -29 22 47.2

with an uncertainty of 2.1 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.73 (+/-0.24).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.7 (+/-0.5). The
best-fitting absorption column is  2.9 (+2.9, -1.9) x 10^21 cm^-2, in
excess of the Galactic value of 8.8 x 10^19 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.4 x 10^-11 (5.7 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.9 (+2.9, -1.9) x 10^21 cm^-2
Galactic foreground: 8.8 x 10^19 cm^-2
Excess significance: 2.5 sigma
Photon index:      1.7 (+/-0.5)

If the light curve continues to decay with a power-law decay index of
1.73, the count rate at T+24 hours will be 1.2 x 10^-5 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.4 x
10^-16 (7.1 x 10^-16) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00868312.

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


GRB_name: GRB181023A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23376
SUBJECT: GRB 181023A: Swift/UVOT Upper Limits
DATE:    18/10/24 00:52:14 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 181023A: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181023A
200 s after the BAT trigger (Marshall et al., GCN Circ. 23366).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 23369)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC           200          350          147         >20.1
white              200         2078          470         >20.8
v                  356         2128          194         >19.4
b                  455         2054          175         >20.3
u                  430         2029          175         >19.6
w1                 406         2005          175         >19.6
m2                 554         1803           78         >19.2
w2                 679         2104          175         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181023A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23377
SUBJECT: GRB 181023A: Swift-BAT refined analysis 
DATE:    18/10/24 01:39:15 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(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 181023A (trigger #868427)
(Marshall et al., GCN Circ. 23366).  The BAT ground-calculated position is
RA, Dec = 248.322, 19.581 deg which is
  RA(J2000)  =  16h 33m 17.4s
  Dec(J2000) = +19d 34' 51.2"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 53%.

The mask-weighted light curve shows a complex structure with some
weak overlapping pulses that starts at ~T-30 s and ends at ~T+40 s.
Note that the burst entered the BAT FOV at T-48 s, and hence there might
be additional emission beforehand. T90 (15-350 keV) is 58.0 +- 8.8 sec (estimated
error including systematics).

The time-averaged spectrum from T-27.62 to T+36.68 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.74 +- 0.24.  The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+32.18 sec in the 15-150 keV band
is 1.0 +- 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/868427/BA/


GRB_name: GRB180728B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23379
SUBJECT: GRB 180728B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 554505003)
DATE:    18/10/24 19:40:05 GMT
FROM:    Michael Coughlin at Caltech/LIGO  <mcoughli@caltech.edu>

Authors: Michael W. Coughlin (Caltech), TomÃ¡s Ahumada (UMD), S.
Bradley Cenko (NASA GSFC), Shaon Ghosh (UWM), Virginia Cunningham
(UMD), Eric C. Bellm (UW), Mansi M. Kasliwal (Caltech) and Leo P.
Singer (NASA GSFC) on behalf of the ZTF and GROWTH collaborations

We observed the localization region of the short GRB 180728B (trigger
554505003) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi
satellite with the Palomar 48-inch telescope equipped with the 47
square degree Zwicky Transient Facility (ZTF) camera. The observations
taken during the night of July 29 did not cover the IPN updated
localization of GRB 180628B available the next day.  The IPN region
was observed with ZTF beginning at 04:06 UT on 2018 July 30 (30:58
hours after the trigger time). The observations covered 334 square
degrees, corresponding to ~ 76% of the probability enclosed in the
localization region.

The images were processed through the ZTF reduction and image
subtraction pipelines at IPAC to search for potential counterparts. 7
high-significance transient and variable candidates were identified by
our pipeline in the area observed, all of which had previous
detections with ZTF in the days and weeks prior to the GRB trigger
time (e.g., supernovae, active galactic nuclei). No viable optical
counterparts were thus identified.

The median 5-sigma upper limit for an isolated point source in our
images was r > 18.7 and g > 20. mag for the observations made on July
30.

ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL
#11266), and includes IPAC; WIS, Israel; OKC, Sweden; JSI/UMd, USA;
UW, USA; DESY, Germany; NRC, Taiwan; UW Milwaukee, USA and LANL USA.
ZTF acknowledges the generous support of the NSF under AST MSIP Grant
No 1440341. Alert distribution service provided by DIRAC@UW. Alert
filtering is being undertaken by the GROWTH marshal system, supported
by NSF PIRE grant 1545949.


GRB_name: GRB181027A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23383
SUBJECT: GRB 181027A: Swift detection of a burst
DATE:    18/10/27 01:57:37 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL)
and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 01:48:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181027A (trigger=868984).  Swift could not slew to the
burst due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 225.383, +30.891 which is 
   RA(J2000) = 15h 01m 32s
   Dec(J2000) = +30d 53' 28"
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 80 sec.  The peak count rate
was ~1200 counts/sec (15-350 keV), at ~49 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 03:50 UT on 2018 November 06. There will thus be no XRT
or UVOT data for this trigger before this time. 

Burst Advocate for this burst is A. Y. Lien (amy.y.lien 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: GRB181027A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23384
SUBJECT: GRB 181027A: Swift-BAT refined analysis
DATE:    18/10/27 13:06:40 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 181027A (trigger #868984)
(Lien, et al., GCN Circ. 23383).  The BAT ground-calculated position is
RA, Dec = 225.361, 30.937 deg which is
    RA(J2000)  =  15h 01m 26.7s
    Dec(J2000) = +30d 56' 12.6"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.
  
The mask-weighted light curve shows a weak emission followed by a bright peak.
The emission starts at T-18.4 sec, peaks at T+47.5 sec and ends at T+85.4 sec.
T90 (15-350 keV) is 81.16 +- 10.55 sec (estimated error including systematics).

The time-averaged spectrum from T-18.45 to T+85.44 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.42 +- 0.09.  The fluence in the 15-150 keV band is 2.8 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+47.81 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/868984/BA/


GRB_name: GRB181027A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23385
SUBJECT: GRB 181027A: Fermi GBM detection
DATE:    18/10/27 19:12:34 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres (UAH) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:

"At 01:49:47.31 UT on 27 October 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181027A (trigger 56229779 / 181027076),
which was also detected by the Swift/BAT (Lien et al. 2018, GCN 23383).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 61
degrees.

The GBM light curve consists of two pulses
with a duration (T90) of about 90 s (50-300 keV).
The time-averaged spectrum from T0-84.5 s to T0+44.5 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.10 +/- 0.09 and
the cutoff energy, parameterized as Epeak, is 183 +/- 27 keV.

The event fluence (10-1000 keV) in this time interval is
(7.76 +/- 0.57)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.64 s in the 10-1000 keV band
is 2.48 +/- 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: GRB181028A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23386
SUBJECT: GRB 181028A: Fermi-LAT detection
DATE:    18/10/29 00:05:28 GMT
FROM:    Magnus Axelsson at Stockholm U.  <magaxe@kth.se>

M. Axelsson (KTH and Stockholm Univ.), D. Kocevski (NASA/MSFC), E. Bissaldi (Politecnico & INFN Bari) and M. Yassine (Univ. & INFN Trieste) report on behalf of the Fermi-LAT team:

On October 28, 2018, Fermi-LAT detected high-energy emission from GRB 181028A, which was also detected by Fermi-GBM (trigger 562428587).

The best LAT on-ground location is found to be

RA, Dec = 88.9, -22.0 (J2000)

with an error radius of 0.4 deg (90 % containment, statistical error only). This is 4.9 deg from the GBM location.

This was 60 deg from the LAT boresight at the time of the GBM trigger: 14:09:42.53 UT.

The data from the Fermi-LAT in the time interval 0-300s after the GBM trigger show a significant increase in the event rate that is spatially correlated with the trigger with very high significance. The highest-energy photon is a 1.7 GeV event which is observed 295 seconds after the GBM trigger.


The Fermi-LAT point of contact for this burst is Manal Yassine (mychbib@gmail.com<mailto:mychbib@gmail.com>).

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: GRB181028A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23387
SUBJECT: GRB 181028A: Fermi GBM observation
DATE:    18/10/29 16:03:48 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:


"At 14:09:42.53 UT on 28 October 2018,
the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181028A
(trigger 562428587/ 181028590),
which was also detected by the
Fermi-LAT (Axelsson et al. 2018, GCN 23386).
The GBM on-ground location is
consistent with the LAT position.

The angle from the Fermi-LAT boresight
at the GBM trigger time is 58 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 30 s (50-300 keV).
The time-averaged spectrum from T0 to T0+30 s
is adequately by a power law function with
an exponential high-energy cutoff.
The power law index is -0.72 +/- 0.02 and
the cutoff energy, parameterized as Epeak,
is 326 +/- 10 keV.

The event fluence (10-1000 keV) in this time interval
is (3.35 +/- 0.05)E-05 erg/cm^2.
The 1-sec peak photon flux measured
starting from T0+26.5 s in the 10-1000 keV band
is 10.3 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 306 +/- 13  keV, alpha = -0.69 +/- 0.03,
and beta = -2.66 +/- 0.24.


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


GRB_name: GRB181028A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23388
SUBJECT: IPN Triangulation of GRB 181028A (long)
DATE:    18/10/29 17:45:10 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

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

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

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

The long-duration GRB 181028A
(Fermi-LAT detection: Axelsson et al., GCN Circ. 23386;
Fermi-GBM detection: Bissaldi et al., GCN Circ. 23387)
was detected by Fermi (GBM trigger 562428587), Konus-Wind,
INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND),
at about 50982 s UT (14:09:42).

We have triangulated it to a preliminary, 3 sigma error box whose 
coordinates are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    88.889 (05h 55m 33s) -21.163 (-21d 09' 49")
  Corners:
    89.470 (05h 57m 53s) -21.496 (-21d 29' 47")
    89.355 (05h 57m 25s) -22.345 (-22d 20' 42")
    88.311 (05h 53m 15s) -20.824 (-20d 49' 27")
    88.431 (05h 53m 43s) -19.956 (-19d 57' 23")
  ---------------------------------------------
The error box area is about 1.0 sq. deg, and its maximum
dimension is 2.539 deg (the minimum one is 33.12 arcmin).
The Sun distance was about 114 deg.

This box intersects the Fermi-LAT 90% CL error circle
(Axelsson et al., GCN Circ. 23386) to form an error box
whose area is about 4 times smaller than that of the LAT
error circle.

This box may be further improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB181028_T50984/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB181030A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23389
SUBJECT: GRB 181030A: Swift detection of a burst with a possible optical counterpart
DATE:    18/10/30 01:50:20 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

E. Sonbas (Adiyaman Univ.), J.D. Gropp (PSU), J. A. Kennea (PSU),
A. Y. Lien (GSFC/UMBC), M. J. Moss (George Washington University),
K. L. Page (U Leicester), M. H. Siegel (PSU) and A. Tohuvavohu (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 01:27:22 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181030A (trigger=869494).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 146.922, +14.658 which is 
   RA(J2000) = 09h 47m 41s
   Dec(J2000) = +14d 39' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual with an image trigger, the available
BAT light curve shows no significant structure. 

The XRT began observing the field at 01:29:44.2 UT, 142.1 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 146.9251, 14.6582 which is equivalent to:
   RA(J2000)  = 09h 47m 42.02s
   Dec(J2000) = +14d 39' 29.5"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 10 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 5.25e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 118 seconds with the White
filter  starting 151 seconds after the BAT trigger. There is a
possible afterglow in the  rapidly available 2.7'x2.7' sub-image near
the position of the XRT afterglow. A  precise position is unavailable
due to a failed aspect correction.  The estimated magnitude is 18.94
with a 1-sigma error of about  0.22. 

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


GRB_name: GRB181030A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23390
SUBJECT: GRB 181030A: SAO RAS optical observations
DATE:    18/10/30 03:51:54 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

A. S. Moskvitin and O. I. Spiridonova (SAO RAS)
report on behalf of larger collaboration.

We observed the field of GRB 181030A (Sonbas et al., GCNC #23389)
with the Zeiss-1000 telescope of SAO RAS (+ CCD photometer)
on the October, 30.

The observations started since 10 minutes after the trigger
(UT_start = 01:37:35, UT_end = 02:49:36).
We obtained 12 x 300 sec. images in Rc band. We detect the OT
discovered by the Swift/UVOT at the position (+/- 1"):

R. A. (2000) =  09:47:42.3
Decl. (2000) = +14:39:25.8

The OT magnitude is R = 19.12 +/- 0.03 (UT_mid = 02:13:35).

Calibrations were made against the nearby SDSS stars
(magnitudes transformed to Rc according to the Lupton, 2005).


GRB_name: GRB181030A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23391
SUBJECT: GRB 181030A: Enhanced Swift-XRT position
DATE:    18/10/30 05:16:25 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2439 s of XRT Photon Counting mode data and 6 UVOT
images for GRB 181030A, 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 = 146.92603, +14.65731 which is equivalent
to:

RA (J2000): 09h 47m 42.25s
Dec (J2000): +14d 39' 26.3"

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: GRB181030A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23392
SUBJECT: GRB 181030A: MASTER Net OT detection
DATE:    18/10/30 06:57:40 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina,  P.Balanutsa, A.Kuznetsov, V.Vladimirov, D. Vlasenko
Lomonosov Moscow State University, SAI, Physics Department

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

D. Buckley,
South African Astronomical Observatory

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

O. Gres, N.M. Budnev, O.Ershova, Yu.Ishmuhametov
Applied Physics Institute, Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez, F. Podesta, C.Francile
Observatorio Astronomico Felix Aguilar (OAFA)

H. Levato
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)


MASTER Global Robotic Net (http://observ.pereplet.ru , 
Lipunov et al. Advances in Astronomy, 2010, 30L http://adsabs.harvard.edu/abs/2010AdAst2010E..30L)
started Swift GRB 181030A (Sonbas et al. GCN23389, Beardmore et al. GCN23391)
optical alert observations 21 sec after notice time at  2018-10-30 01:29:03 UT

MASTER-Kislovodsk robotic telescope, located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory)
  was pointed to the  GRB181030A 21 sec after notice time and 101 sec after trigger time at 2018-10-30 01:29:03 UT.
On our first 20s expos. set , started at 2018-10-30 01:29:03 UT,
we  found optical transient within SWIFT error-box
MASTER OT J094742.25+143925.73 (also detected by Sonbas et al SwiftUVOT GCN23389 and by Moskvitin et al. GCN 23390)
with m_OT=16.5 and falling light curve in both polarization filters.

The galactic latitude b = 46 deg., longitude l = 220 deg.
The observations made on zenit distance = 47 deg.
The moon (68 % bright part) was 67 deg. above the horizon.The distance between  moon and  object was 39 deg
The sun  altitude  was -24.2 deg.

MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station)
was pointed to the  GRB181030A 31 sec after notice time and 105 sec after 
trigger time at 2018-10-30 01:29:13 UT.
The observations started on zenit distance = 51 deg.
The moon (68 % bright part) was 66 deg. above the horizon. The distance between  moon and  object was 39
The sun  altitude  was -27.9 deg.


GRB_name: GRB181028A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23393
SUBJECT: Konus-Wind observation of GRB 181028A
DATE:    18/10/30 10:36:15 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 181028A
(Fermi-LAT detection: Axelsson et al., GCN Circ. 23386;
Fermi-GBM observation: Bissaldi & Meegan, GCN Circ. 23387;
IPN Triangulation: Hurley et al., GCN Circ. 23388)
triggered Konus-Wind at T0=50984.309 s UT (14:09:44.309).

The burst light curve shows a multipeaked structure
which starts at ~T0-2 s and has a total duration of ~38 s.
The emission is seen up to ~4 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.43(-0.18,+0.20)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+26.064 s,
of 4.06(-1.01,+1.03)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+40.704 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.72(-0.10,+0.11)
and Ep = 286(-22,+26) keV (chi2 = 53/70 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.6
(chi2 = 53/69 dof).

The spectrum near the maximum count rate
(measured from T0+24.320 to T0+32.512 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model
with  alpha = -0.39(-0.23,+0.27)
and Ep = 292(-37,+49) keV (chi2 = 70/70 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.1
(chi2 = 70/69 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181028_T50984/

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


GRB_name: GRB181030A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23394
SUBJECT: GRB 181030A: Swift-XRT refined Analysis
DATE:    18/10/30 12:14:27 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU), B.
Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA) and E. Sonbas report on behalf of the Swift-XRT team:

We have analysed 7.2 ks of XRT data for GRB 181030A (Sonbas et al. GCN
Circ. 23389), from 148 s to 32.8 ks after the  BAT trigger. The data
comprise 121 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 23391).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.3 (+0.5, -0.7), followed by a break at T+179 s to an
alpha of 1.815 (+0.024, -0.023).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.06 (+0.05, -0.04). The
best-fitting absorption column is  5.3 (+1.9, -1.8) x 10^20 cm^-2, in
excess of the Galactic value of 3.5 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.54 (+0.17, -0.14)
and a best-fitting absorption column of 5.2 (+4.9, -1.7) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.2 x 10^-11 (4.5 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.2 (+4.9, -1.7) x 10^20 cm^-2
Galactic foreground: 3.5 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.54 (+0.17, -0.14)

If the light curve continues to decay with a power-law decay index of
1.815, the count rate at T+24 hours will be 1.0 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.4 x
10^-14 (4.7 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/00869494.

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


GRB_name: GRB181026A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23395
SUBJECT: GRB 181026A: AstroSat CZTI detection
DATE:    18/10/30 13:23:35 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

T. Khanam (IUCAA), V. Bhalerao (IIT-B), V. Sharma, A. Vibhute and D. Bhattacharya (IUCAA),  A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 181026A, which was also detected by Fermi (GBM trigger name: bn181026540) at about 12:57:00.037 UT.

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 12:57:01.50 UT. The measured peak count rate is 251.2 cts/s above the background in combined data of four quadrants, with a total of 2454 cts. The local mean background count rate was 524 cts/s. Using cumulative rates, we measure a T90 of 30.2 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB181030A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23396
SUBJECT: GRB 181030A: RATIR Optical and NIR Observations 
DATE:    18/10/30 15:56:06 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:

We observed the field of GRB 181030A (Sonbas et al., GCN Circ. 23389)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir from 2018/10 30.41 to
2018/10 30.53 UTC (8.40 to 11.29 hours after the BAT trigger), obtaining
a total of 0.82 hours exposure in the r and i bands and 0.39 hours
exposure in the Z, Y, J, and H bands.

For a source within the XRT error circle, in comparison with the SDSS
DR9 and 2MASS catalogs, we obtain the following upper limits (3-sigma):

  r > 22.25
  i > 22.11
  Z > 21.07
  Y > 20.80
  J > 20.31
  H > 19.61

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

The afterglow has clearly faded since the early observations of Sonbas
et al. (GCN Circ. 23389), Moskvitin & Spiridonova (GCN Circ. 23390), and
Lipunov et al. (GCN Circ. 23392).

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro
MÃ¡rtir.


GRB_name: GRB181030A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23397
SUBJECT: GRB 181030A, Swift-BAT refined analysis
DATE:    18/10/30 22:49:32 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 181030A (trigger #869494)
(Sonbas et al., GCN Circ. 23389).  The BAT ground-calculated position is
RA, Dec = 146.916, 14.657 deg which is
  RA(J2000)  =  09h 47m 39.8s
  Dec(J2000) = +14d 39' 26.5"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 71%.

The mask-weighted light curve shows a long pulse that starts at ~T0 and peaks
at ~T+70 s. The main pulse emission ends at ~T+200 s, with some weak emission lasting
till ~T+400 s. T90 (15-350 keV) is 304.7 +- 76.9 sec (estimated error including systematics).

The time-averaged spectrum from T+3.2 to T+443.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.77 +- 0.09.  The fluence in the 15-150 keV band is 6.2 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+71.33 sec in the 15-150 keV band
is 0.8 +- 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/869494/BA/


GRB_name: GRB181028A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23399
SUBJECT: GRB 181028A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/10/31 11:40:37 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 181028A (Fermi-LAT detection: Axelsson et al., GCN Circ. 23386;
Fermi-GBM observation: Bissaldi & Meegan, GCN Circ. 23387;
IPN Triangulation: Hurley et al., GCN Circ. 23388;
Konus-Wind observation: Kozlova et al., GCN Circ. 23393)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 14:09:39.546 UTC
on 28 October 2018. The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure
which starts at T+2.6 sec, peaks at T+14.4 sec, and ends at T+32.1 sec.
The T90 and the T50 durations measured by the SGM data are
25.4 +- 5.5 sec and 8.3 +- 0.9 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1224770949/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.


GRB_name: GRB181030A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23400
SUBJECT: GRB 181030A: Swift/UVOT Detection
DATE:    18/10/31 13:40:13 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181030A
152 s after the BAT trigger (Sonbas et al., GCN Circ. 23389).
A fading source is detected in the initial UVOT exposures at a position
consistent with the XRT position (Beardmore et al., GCN Circ. 23391) and
also with SAO RAS (Moskvitin et al., GCN Circ. 23390) and MASTER Net
(Lipunov et al., GCN Circ. 23392).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC           152          270          116        19.34 +/- 0.30
white             3978         5614          393        >20.7
v                 4389         6009          378        >18.9
b                 3774        17487          635        >20.1
u                 3569        17236         1278        >20.3
uvw1              4799        11747          852        >20.2
uvm2              4594        22498         1201        >20.7
uvw2              4184         5819          393        >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181103A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23402
SUBJECT: GRB 181103A: Swift detection of a burst
DATE:    18/11/03 04:58:42 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

A. Tohuvavohu (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
K. L. Page (U Leicester), M. H. Siegel (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 04:22:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181103A (trigger=870201).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 197.109, +52.230 which is 
   RA(J2000) = 13h 08m 26s
   Dec(J2000) = +52d 13' 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 10 sec.  The peak count rate
was ~600 counts/sec (15-350 keV), at ~ 2 sec after the trigger. 

The XRT began observing the field at 04:24:00.8 UT, 90.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 197.1161,
52.2254 which is equivalent to:
   RA(J2000)  = 13h 08m 27.86s
   Dec(J2000) = +52d 13' 31.4"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 22 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 (1.31 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 5.5
(+3.93/-3.31) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 92 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 A. Tohuvavohu (aaronb AT swift.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: GRB181103A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23403
SUBJECT: GRB 181103A: Enhanced Swift-XRT position
DATE:    18/11/03 09:58:38 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 997 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 181103A, 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 = 197.11587, +52.22587 which is equivalent
to:

RA (J2000): 13h 08m 27.81s
Dec (J2000): +52d 13' 33.1"

with an uncertainty of 1.6 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: GRB181103A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23404
SUBJECT: GRB 181103A: Swift-XRT refined Analysis
DATE:    18/11/03 12:15:07 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU),
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB) and A. Tohuvavohu report on behalf of the Swift-XRT team:

We have analysed 6.4 ks of XRT data for GRB 181103A (Tohuvavohu et al.
GCN Circ. 23402), from 76 s to 18.3 ks after the  BAT trigger. The data
comprise 8 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Evans et al. (GCN Circ.
23403).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.40 (+/-0.04).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.14 (+0.21, -0.20). The
best-fitting absorption column is  6.0 (+1.3, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 1.3 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.9 x 10^-11 (7.3 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.0 (+1.3, -1.1) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^20 cm^-2
Excess significance: 8.5 sigma
Photon index:      2.14 (+0.21, -0.20)

If the light curve continues to decay with a power-law decay index of
0.40, the count rate at T+24 hours will be 0.032 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x
10^-12 (2.3 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/00870201.

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


GRB_name: GRB181103A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23405
SUBJECT: GRB 181103A: Swift-BAT refined analysis
DATE:    18/11/03 13:47:23 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), A. Tohuvavohu (PSU),
T. N. Ukwatta (LANL) (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 181103A (trigger #870201)
(Tohuvavohu, et al., GCN Circ. 23402).  The BAT ground-calculated position is
RA, Dec = 197.093, 52.220 deg which is 
   RA(J2000)  =  13h 08m 22.3s 
   Dec(J2000) = +52d 13' 11.8" 
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 78%.

The mask-weighted light curves shows a single FRED-shaped peak from 
T0-1 sec, peaking at T0, and decaying to background by T0+10 sec.
T90 (15-350 keV) is 8.38 +- 2.41 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.89 to T+10.18 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.90 +- 0.27.  The fluence in the 15-150 keV band is 2.8 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.46 sec in the 15-150 keV band
is 0.8 +- 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/870201/BA/


GRB_name: GRB181103A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23406
SUBJECT: GRB 181103A: Nanshan-1m optical upper limit
DATE:    18/11/04 11:51:29 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

J.H. Liu (XAO), Z.P. Zhu, D. Xu (NAOC), X. Zhang, F.F. Song, Z.X. Li, 
J.Y. Bai, H.B. Niu, J.Z. Liu, A. Esamdin, L. Ma, Y. Zhang (XAO) report:

We observed the field of GRB 181103A (Tohuvavohu et al., GCN 23402) 
using the Nanshan-1m telescope located at Nanshan, Xinjiang, China. We 
optained 5300s, 1400s, 1600s R-band frames, starting at 23:07:05 UT 
on 2018-11-03, i.e, 18.73 hr after the Swift trigger.

No optical source was detected in the stacked image at the XRT position 
(Evans et al, GCN 23403), down to a limiting magnitude of R ~ 21.3 mag 
at the median time of 19.31hr post-burst, calibrated with the nearby 
SDSS field.


GRB_name: GRB181103A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23407
SUBJECT: GRB 181103A: Swift/UVOT Detection
DATE:    18/11/04 14:47:19 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 181103A: Swift/UVOT Detection

S. J. LaPorte (PSU) and A. Tohuvavohu (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181103A
92 s after the BAT trigger (Tohuvavohu et al., GCN Circ. 23402).
A fading source is detected in the initial UVOT exposures at a position
consistent with the XRT position (Evans et al., GCN Circ. 23403).

Preliminary detections and 3-sigma upper limits using the UVOT photometric
system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

b              534           898            58          >19.08
uvm2           632          1126            57          >18.19
u              279           874           530           19.58+-0.25 
v              608          1103            58          >18.21
uvw1           657           849            38          >18.16
uvw2           584          1079            58          >18.36
white_FC          121           271           294           20.47+-0.29 
white       559          6763           579          >21.12  

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181103A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23408
SUBJECT: GRB 181103A: MITSuME Okayama optical upper limits
DATE:    18/11/05 04:35:48 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

K. L. Murata, R. Itoh, Y. Tachibana, S. Harita, K. Morita, K. Shiraishi, K.
Iida, M. Oeda, M. Niwano, R. Adachi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 181103A (A. Tohuvavohu  et
al., GCN Circular #23402) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of  Okayama Astrophysical
Observatory, Japan.

The observation started on 19:38:58 UT. We did not find any new point
source within enhanced XRT circle (P.A. Evans et al., GCN Circular #23403)
in all three bands. We obtained following limits for the magnitudes.

T0+[hour]    MID-UT      T-EXP[sec]    g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
15.352       20:15:29          3240      >18.5     >18.0     >17.5
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.


GRB_name: GRB181028A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23409
SUBJECT: GRB 181028A: Insight-HXMT/HE detection
DATE:    18/11/05 05:15:22 GMT
FROM:    Ce Cai at IHEP  <caice@ihep.ac.cn>

C. Cai, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2018-10-28T14:09:43.000 (T0), the Insight-HXMT/HE detected 
GRB 181028A (trigger ID: HEB181028590) in a routine search of the data, 
which was also triggered by Fermi/LAT (Axelsson et al.,GCN 23386);
Fermi/GBM (Bissaldi et al.,GCN 23387); 
IPN Triangulation (Hurley et al.,GCN 23388); 
Konus-Wind observation (Kozlova et al., GCN 23393);
CALET/GBM (A. Yoshida et al., GCN 23399). 

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 23.58 s measured from T0-4.53 s. 
The 1-s peak rate, measured from T0+14.63 s, is 1351.0 cnts/s. 
The total counts from this burst is 11055.5 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB181028590_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
GRB mode with the energy range of about 200-3000 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB181103A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23410
SUBJECT: GRB 181103A: AbAO optical upper limit
DATE:    18/11/05 08:51:38 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova  (IKI),   A. Pozanenko (IKI), R. Inasaridze (AbAO), E. 
Mazaeva (IKI),  S. Belkin (IKI), V. Ayvazian  (AbAO),  O. Kvaratskhelia 
(AbAO), G. Kapanadze (AbAO), I. Molotov (KIAM) report on behalf of 
larger GRB follow-up collaboration:

We observed the field of the Swift GRB 181103A (Tohuvavohu et al., GCN 
23402) with AS-32 (0.7m) telescope of Abastumani Observatory starting on 
  Nov. 3 (UT) 15:02:42.   We do not detect any object within  enhanced 
XRT position (Evans et al., GCN 23403). In particular we do not detect 
the source reported by LaPorte et al. (GCN 23407). Preliminary 
photometry of the field is following:

Date       UT start   t-T0      Filter Exp.   OT    Err. UL
                      (mid, days)       (s)

2018-11-03 15:02:42   0.47151   R      63*60  n/d   n/d  20.5

The photometry is based on nearby SDSS-DR12 stars (R, Lupton 
transformation).


GRB_name: GRB181110A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23413
SUBJECT: GRB 181110A: Swift detection of a burst with an optical counterpart
DATE:    18/11/10 08:59:09 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

P. A. Evans (U Leicester), K. L. Page (U Leicester) and
T. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 08:43:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181110A (trigger=871316).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 302.342, -36.903 which is 
   RA(J2000) = 20h 09m 22s
   Dec(J2000) = -36d 54' 08"
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 150 sec.  The peak count rate
was ~3870 counts/sec (15-350 keV), at ~10 sec after the trigger. 

The XRT began observing the field at 08:44:35.2 UT, 64.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 302.31711, -36.89632 which
is equivalent to:
   RA(J2000)  = 20h 09m 16.11s
   Dec(J2000) = -36d 53' 46.8"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 75 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 0.1 s image was 5.82e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 72 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 20:09:16.28 = 302.31782
  DEC(J2000) = -36:53:47.8  = -36.89661
with a 90%-confidence error radius of about 0.63 arc sec. This position is 3.3
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.39 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.07. 

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


GRB_name: GRB181110A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23414
SUBJECT: GRB 181110A: Kanata 1.5m optical observation
DATE:    18/11/10 10:26:30 GMT
FROM:    Koji Kawabata at HASC,Hiroshima U  <kawabtkj@hiroshima-u.ac.jp>

M. Yamanaka, M. Kawabata, K. S. Kawabata (Hiroshima Univ.) 
report on behalf of Kanata team:

We performed optical imaging polarimetry to the field of the
GRB 181110A (Evans et al. GCN 23413) from 2018-11-10 08:44:48 UT 
(77 seconds after the trigger) with HOWPol attached to the 1.5-m 
Kanata telescope at Higashi-Hiroshima Observatory, Japan. Although
the first frames were severely affected by bright twilight sky, 
in later frames a possible bright optical counterpart of the GRB 
appeared at the position consistent with the Swift-UVOT observation
(Evans et al. GCN 23413). The magnitude of the counterpart was 
R~14 mag (USNO B1.0) at 940 seconds after the trigger, suggesting
it brightened by ~4 mag within ~15 minutes. It further brightened
slightly (by a few 0.1 mag) and then declined smoothly. 
Further analysis is ongoing.


GRB_name: GRB181110A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23415
SUBJECT: GRB 181110A: MITSuME Akeno optical observation
DATE:    18/11/10 12:11:22 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

K. L. Murata, R. Itoh, Y. Tachibana, S. Harita, K. Morita,
K. Shiraishi, K. Iida, M. Oeda, M. Niwano, R. Adachi, Y. Yatsu, and N.
Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration

We searched for the optical counterpart of GRB 181110A (Evans  et al., GCN
Circular #23413) with the optical three color (g', Rc, and Ic) CCD cameras
attached to the MITSuME 50 cm telescope of AkenoObservatory, Yamanashi,
Japan.

The observation for the position of the 1st GCN of this trigger (trigger
#871316) started on 08:44:56 UT which corresponds to 85 sec after the
trigger.

Here we report the result of the images after 08:55:15 UT.
We detected the point source at the position consistent with the Swift/UVOT
observation (Evans  et al., GCN Circular #23413) and the Kanata observation
(Yamanaka et al., GCN Circular # 23414).
The measured magnitudes are listed as follows.

T0+[min]    MID-UT      T-EXP[sec]        g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
~12      09:00:58.3           420               ~14      ~14        ~14
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
The magnitudes are expressed in the AB system.

Further analysis is ongoing.


GRB_name: GRB181110A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23416
SUBJECT: GRB 181110A: optical observations from iTelescope SSO
DATE:    18/11/10 12:45:01 GMT
FROM:    Denis Denisenko at SAI MSU  <d.v.denisenko@gmail.com>

D. Denisenko (SAI MSU), M. Gnetov, E. Guskov, M. Orlova, V. Smirnov,
I. Vodolazskiy, N. Zlobin, D. Fernandez Ortiz (Center on Donskaya,
Moscow) report:

GRB 181110A: optical observations from iTelescope SSO

The field of bright long GRB 181110A (Evans et al., GCN Circ. 23413)
was observed remotely from Siding Spring using iTelescope.Net T17
instrument (0.43-m f/6.8 reflector + FLI PL4710 CCD) on 09:49-09:55
UT. Four unfiltered 60-sec exposures were obtained, until the
telescope was occupied by the other scheduled user. The optical
transient is well detected on 4 images and slowly fading, in
accordance with Yamanaka et al., GCN Circ. 23414. The following
magnitudes were measured using the nearby star USNO-B1.0 0531-0876625
as a reference with R2=14.80 in USNO-B1.0:

TIME-OBS, JD T-T0,s  Mag. Error
-------------------------------
2458432.9093  3952  15.60  0.02
2458432.9105  4055  15.64  0.01
2458432.9117  4156  15.68  0.01
2458432.9128  4257  15.77  0.02
-------------------------------

Comparison of T17 iTelescope.Net image and 1990-09-19 DSS Red plate is
uploaded to http://scan.sai.msu.ru/~denis/GRB/GRB181110A-T17-DSS-anim.gif
(FOV 5'x5', 2x zoom).


GRB_name: GRB181110A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23417
SUBJECT: GRB 181110A: Enhanced Swift-XRT position
DATE:    18/11/10 17:03:06 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2774 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 181110A, 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 = 302.31802, -36.89665 which is equivalent
to:

RA (J2000): 20h 09m 16.32s
Dec (J2000): -36d 53' 47.9"

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: GRB181110A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23418
SUBJECT: GRB 181110A: Swift-XRT refined Analysis
DATE:    18/11/10 18:09:21 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore (U.
Leicester), J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Tohuvavohu (PSU) and
P.A. Evans report on behalf of the Swift-XRT team:

We have analysed 7.4 ks of XRT data for GRB 181110A (Evans et al. GCN
Circ. 23413), from 67 s to 24.8 ks after the  BAT trigger. The data
comprise 260 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN Circ. 23417).

The late-time light curve (from T0+5.2 ks) can be modelled with a
power-law decay with a decay index of alpha=2.10 (+/-0.14).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.88 (+/-0.04). The
best-fitting absorption column is  8.6 (+1.0, -0.9) x 10^20 cm^-2,
consistent with the Galactic value of 7.7 x 10^20 cm^-2 (Willingale et
al. 2013). The PC mode spectrum has a photon index of 1.74 (+0.07,
-0.06) and a best-fitting absorption column consistent with the
Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.8 x 10^-11 (4.3 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      7.7 (+1.5, -0.0) x 10^20 cm^-2
Galactic foreground: 7.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.74 (+0.07, -0.06)

If the light curve continues to decay with a power-law decay index of
2.10, the count rate at T+24 hours will be 2.2 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.3 x
10^-14 (9.3 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/00871316.

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


GRB_name: GRB181110A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23419
SUBJECT: GRB 181110A: Swift/UVOT Detection
DATE:    18/11/10 21:56:35 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181110A
72 s after the BAT trigger (Evans et al., GCN Circ. 23413).
The GRB was detected in ground photometry (Yamanaka et al., GCN
Circ. 23414; Murata et al., GCN Circ. 23415; Denisenko et al.
GCN Circ. 23416).  The UVOT detects a source consistent
with the XRT position (Goad et al. GCN Circ. 23417) in the initial
UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  20:09:16.27 = 302.31781 (deg.)
    Dec (J2000) = -36:53:47.9  = -36.89664 (deg.)
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are:

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

white               72          222          147         18.52 +/- 0.07
v                  614          634           19         16.09 +/- 0.13
b                  540          559           20         16.98 +/- 0.11
u                  284          534          246         16.66 +/- 0.04
w1                 663          683           19         15.65 +/- 0.13
m2                1068         1088           20         14.66 +/- 0.11
w2                1018         1038           20         15.74 +/- 0.14

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).

The source showed a rebrightening with a late peak at around 1100s after
the trigger.


GRB_name: GRB181110A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23420
SUBJECT: GRB 181110A, Swift-BAT refined analysis 
DATE:    18/11/11 01:33:53 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. A. Evans (U Leicester),
H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 181110A (trigger #871316)
(Evans et al., GCN Circ. 23413).  The BAT ground-calculated position is
RA, Dec = 302.330, -36.878 deg which is
  RA(J2000)  =  20h 09m 19.2s
  Dec(J2000) = -36d 52' 41.4"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T-110 s and ends at ~T+130 s. The main peak occurs at ~T+25 s.
T90 (15-350 keV) is 138.4 +- 10.9 sec (estimated error including systematics).

The time-averaged spectrum from T-109.3 to T+129.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.02 +- 0.05.  The fluence in the 15-150 keV band is 9.9 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+25.03 sec in the 15-150 keV band
is 3.7 +- 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/871316/BA/


GRB_name: GRB181110A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23421
SUBJECT: GRB 181110A: VLT/X-shooter redshift
DATE:    18/11/11 12:05:33 GMT
FROM:    Daniel Perley at Liverpool JMU  <d.a.perley@ljmu.ac.uk>

D. A. Perley (LJMU), D. B. Malesani (DAWN/NBI and DARK/NBI), J. P. U.
Fynbo (DAWN/NBI and DAWN/DTU), K. E. Heintz (Univ. Iceland), D. A. Kann
(HETH/IAA-CSIC), V. D'Elia (SSDC), L. Izzo (HETH/IAA-CSIC), and N. R.
Tanvir (Univ. Leicester) report:

We observed the optical counterpart of GRB 181110A (Evans et al. GCN
23413; Yamanaka et al., GCN 23414; Murata et al. GCN 23415) with the
ESO-VLT UT2 equipped with the X-shooter spectrograph.  We acquired four
600 second spectra on UT 2018-11-11 between 00:36 and 01:21,
approximately 16 hours after the GRB.  The optical afterglow was R~20.4
at this time.

Continuum is detected in the reduced spectrum across the entire spectral
range of the instrument (blue limit of 3000 Angstroms).  Several weak
absorption features are also detected: in particular, we identify Mg II
and Fe II at a common redshift of z=1.505, identifying this as the most
likely redshift of the GRB.  An additional intervening system is also
identified from (probable) Mg II absorption at z=0.28.

We acknowledge the ESO observing staff at Paranal, including Stephane
Brillant and Eleonora Sani.


GRB_name: GRB181110A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23422
SUBJECT: GROND observations of GRB181110A
DATE:    18/11/11 13:17:04 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan@bolmer.de>

J. Bolmer (MPE, Garching) and P. Schady (Univ. of Bath) report:

We observed the field of GRB 181110A (Swift trigger 871316; Evans et al., GCN #23413)
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted
at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).

Observations started at 00:01 UT, 15.5 hrs after the GRB trigger, and were performed
under poor seeing conditions, 4.1â€œ, and at an average airmass of 1.2.

We detect a source at a position consistent with the X-ray and optical afterglow
(Evans et al., GCN #23413; Kuin et al., GCN #23419). Based on the first 17 min of
total exposures in g'r'i'z' and 20 min in JHK, we measure the following preliminary
AB magnitudes:

g' = 21.25 +/- 0.06 mag
r' = 20.58 +/- 0.05 mag
i' = 19.91 +/- 0.08 mag
z' = 20.08 +/- 0.09 mag
J = 20.16 +/- 0.20 mag
H = 19.76 +/- 0.18 mag
K = 19.27 +/- 0.18 mag

Given magnitudes are calibrated against USNO and 2MASS field stars and are not corrected
for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.06
in the direction of the burst (Schlafly & Finkbeiner 2011).


GRB_name: GRB181110A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23423
SUBJECT: GRB 181110A: optical observations in Chilescope observatory
DATE:    18/11/11 18:27:48 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), E. Mazaeva (IKI), A. Volnova (IKI) 
  report on behalf of IKI-FuN follow-up collaboration:

We observed  the field of  GRB 181110A   (Evans et al., GCN 23413)  with 
RC-1000 telescopes of CHILESCOPE observatory. Observation started on 
Nov. 11 (UT) 01:02:08 in r'-filter and were performed under moderate 
seeing conditions of 1.5''.  We detect optical afterglow  (Evans et al., 
GCN 2341;  Yamanaka et al., GCN  23414; Murata et al., GCN  23415; 
Denisenko et al., GCN   23416; Perley et al., GCN  23421; Bolmer  et 
al., GCN   23422).

Preliminary photometry in AB is following.

Date       UT start t-T0    Filter Exp.   OT    Err. UL
                     (mid, days)    (s)

2018-11-11 01:02:08 0.69979 r'     10*300 20.53 0.10 22.8

The photometry is based on several nearby stars, magnitudes taken from 
NOMAD catalog and Jester et al. (2005) transformations.


GRB_name: GRB181110A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23424
SUBJECT: Konus-Wind observation of GRB 181110A
DATE:    18/11/12 14:38:18 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov,
and T. Cline, on behalf of the Konus-Wind team, report:

The long GRB 181110A (Swift-BAT trigger #871316: (Evans et al.,
GCN  23413; Lien et al., GCN 23420; T0(BAT)= 08:43:31.320 UT)
was detected by Konus-Wind (KW) in the waiting mode.

A Bayesian block analysis of the KW waiting mode data in
the 22-380 keV band reveals a count rate increase in the interval
from ~T0(BAT)-42 s to ~T0(BAT)+98 s.
No statistically significant emission has been detected above
380 keV.

The KW light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB181110A/

Modeling the KW 3-channel spectrum (from T0(BAT)-36 s to T0(BAT)+32 s)
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.63(-0.26,+0.34) and Ep = 48(-27,+14) keV.

The total burst fluence in the 15-1500 keV band
is (1.1 Â± 0.2)x10^-5 erg/cm^2.

Assuming z = 1.505 (Perley et al., GCN 23421) and a standard cosmology
model with H_0 = 70 km/s/Mpc, Omega_M = 0.30, and Omega_Lambda = 0.70, 
the burst isotropic energy release E_iso is ~1.1x10^53 erg (1-10000 keV,
rest frame), and the rest-frame peak energy is ~120 keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.


GRB_name: GRB181120A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23427
SUBJECT: GRB 181120A: Fermi-LAT detection
DATE:    18/11/20 17:37:37 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari), M. Axelsson (KTH ans Stockholm Univ.),
G. Vianello (Stanford Univ.), F. Longo (Univ. & INFN Trieste), and
D. Kocevski (NASA/MSFC) report on behalf of the Fermi-LAT team:


On November 20, 2018, Fermi-LAT detected high-energy emission from GRB 181120A,
which was also detected by Fermi-GBM (trigger 181120265 / 564387684).
The best LAT on-ground location is found to be

RA, Dec: 20.38, 4.17 (degrees, J2000)

with an error radius of 1 deg (90% containment, statistical error only).
This was 71 deg from the LAT boresight at the time
of the GBM trigger: T0 = 06:21:19.08 UT.

The data from the Fermi-LAT show a significant (~5 sigma) increase
in the event rate in the time interval 3000-6000 s after the
GBM emission. We note that the LAT location is 16 degrees from the GBM one.
Based on our analysis, we rule out contamination from the Earth limb,
and the nearest known point source is ~2 degrees away.

The photon flux above 100 MeV in the time interval 3000-6000 s after the
GBM trigger is (2.2 +/- 0.7)E-06 ph/cm2/s.
The estimated photon index above 100 MeV is 4.0 +/- 0.9.
We note that the spectrum is softer than the one typically seen from GRBs.
The highest-energy photon is a 410 MeV event which is
observed 5530 seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (elisabetta.bissaldi@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: GRB181120A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23428
SUBJECT: GRB 181120A: Fermi GBM observation
DATE:    18/11/20 21:19:58 GMT
FROM:    Cori Fletcher at USRA/NASA  <corinne.l.fletcher@nasa.gov>

C. Fletcher (USRA) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:

"At  06:21:19.08 UT on 20 November 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181120A (trigger 564387684 / 181120265),
which was also detected by the LAT (Bissaldi et al. 2018, GCN 23427)
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 71 degrees.

The GBM light curve shows a single bright pulse followed by extended emission
with a duration (T90) of about 17 s (50-300 keV).
The time-averaged spectrum from T0-0.5 s to T0+16.9 s is best fit by
a power law function with an exponential
high-energy cutoff.  The power law index is -0.95 +/- 0.08 and
the cutoff energy, parameterized as Epeak, is 158 +/- 14 keV

The event fluence (10-1000 keV) in this time interval is
(4.60 +/- 0.191)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.1 s in the 10-1000 keV band
is 11.5 +/- 0.3 ph/s/cm^2.

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


GRB_name: GRB181121A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23429
SUBJECT: GRB 181121A: AGILE/MCAL detection of a burst
DATE:    18/11/22 08:33:17 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

*A.Ursi (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), *


*N. Parmiggiani (INAF/IASF-Bo), A. Argan, M. Cardillo, Y. Evangelista, G.
Minervini, G. Piano (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor
Vergata), F. Lucarelli, C. Pittori, (SSDC, and INAF/OAR), A. Bulgarelli, V.
Fioretti, F. Fuschino (INAF/IASF-Bo), M. Marisaldi (INAF/IASF-Bo, and
Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma
(ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani
(INAF/IASF-Mi) report on behalf of the AGILE Team:The AGILE
Mini-CALorimeter (MCAL) detected a short burst at T0 = 2018-11-21
20:43:36.283 +/- 0.01 s (UTC).*
*The light curve shows a sharp peak lasting about 0.16 s, that released a
total number of ~334 counts in the detector (in the 0.4-100 MeV energy
range), above an average background rate of 573 counts / s. Two weaker
pulses are present at T0+0.32 s and T0+0.67 s*

*.*
*The GRB is clearly detected also by AGILE scientific ratemeters; in
particular, by the Super-AGILE (20-60 keV), **Anti-Coincidence (50-200
keV), and MCAL (0.4-100 MeV) ratemeters.*



*Further analysis is still in progress.The AGILE-MCAL detector has a full
solid angle acceptance, and is operational in the range 0.4 - 100 MeV.*


GRB_name: GRB181119A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23430
SUBJECT: GRB 181119A: Insight-HXMT/HE detection
DATE:    18/11/22 13:14:55 GMT
FROM:    QiBin Yi at IHEP, HXMT  <yiqb@ihep.ac.cn>

Q. B. Yi, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2018-11-19T14:32:27.200 (T0), the Insight-HXMT/HE detected 
GRB 181119A (trigger ID: HEB181119605) in a routine search of the data,
which was also triggered by Fermi/GBM (trigger number 564330742)

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 14.82 s measured from T0-10.03 s. 
The 1-s peak rate, measured from T0+4.79 s, is 680.6 cnts/s. 
The total counts from this burst is 2060.5 counts. 
URL_LC:  http://www.hxmt.org/images/GRB/HEB181119605_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB181123A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23431
SUBJECT: GRB 181123A: Swift detection of a burst
DATE:    18/11/23 04:30:51 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. Y. Lien (GSFC/UMBC), P. D'Avanzo (INAF-OAB), D. M. Palmer (LANL)
and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 04:19:22 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181123A (trigger=873178).  Swift could not slew to the
burst due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 284.651, -8.237 which is 
   RA(J2000) = 18h 58m 36s
   Dec(J2000) = -08d 14' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual for an image trigger, there is
no obvious variation in the immediately-available BAT lightcurve. 

Due to an observing constraint, Swift will not be able to slew
to the burst until February 19. There will therefore be no XRT or
UVOT data on this burst. 

Burst Advocate for this burst is A. Y. Lien (amy.y.lien 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: GRB181123B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23432
SUBJECT: GRB 181123B: Swift detection of a short burst
DATE:    18/11/23 05:48:16 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. Y. Lien (GSFC/UMBC), P. D'Avanzo (INAF-OAB) and D. M. Palmer (LANL)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 05:33:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181123B (trigger=873186).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 184.348, +14.589 which is 
   RA(J2000) = 12h 17m 23s
   Dec(J2000) = +14d 35' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
structure with a duration of about 0.4 sec.  The peak count rate
was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 05:34:23.3 UT, 80.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 184.36663, 14.59889 which is equivalent
to:
   RA(J2000)  = 12h 17m 27.99s
   Dec(J2000) = +14d 35' 56.0"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 74 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 83 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 A. Y. Lien (amy.y.lien 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: GRB181123B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23433
SUBJECT: GRB 181123B: Prompt enhanced Swift-XRT position
DATE:    18/11/23 06:17:37 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using  promptly downlinked XRT event data for GRB 181123B, we find an
enhanced XRT position of the afterglow: RA, Dec: 184.3670, 14.5979
which is equivalent to:
   RA (J2000)  = 12 17 28.08
   Dec (J2000) = +14 35 52.5
with an uncertainty of 2.1 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/873186.

Position enhancement is 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: GRB181123B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23434
SUBJECT: GRB 181123B: Enhanced Swift-XRT position
DATE:    18/11/23 08:56:08 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 987 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 181123B, 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 = 184.36687, +14.59789 which is equivalent
to:

RA (J2000): 12h 17m 28.05s
Dec (J2000): +14d 35' 52.4"

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: GRB181123B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23435
SUBJECT: GRB 181123B: Swift-XRT refined Analysis
DATE:    18/11/23 11:33:25 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), P.
D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Tohuvavohu (PSU), S. J.
LaPorte (PSU) and A.Y. Lien report on behalf of the Swift-XRT team:

We have analysed 6.3 ks of XRT data for GRB 181123B (Lien et al. GCN
Circ. 23432), from 95 s to 16.0 ks after the  BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Osborne et al. (GCN Circ. 23433).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.31 (+0.15, -0.14).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.99 (+0.30, -0.20). The
best-fitting absorption column is  3.9 (+6.4, -0.8) x 10^20 cm^-2,
consistent with the Galactic value of 3.1 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.2 x 10^-11 (3.6 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.9 (+6.4, -0.8) x 10^20 cm^-2
Galactic foreground: 3.1 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.99 (+0.30, -0.20)

If the light curve continues to decay with a power-law decay index of
1.31, the count rate at T+24 hours will be 1.9 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.1 x
10^-15 (6.7 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/00873186.

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


GRB_name: GRB181020A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23436
SUBJECT: GRB 181020A: AstroSat CZTI detection
DATE:    18/11/23 14:34:19 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, T. Khanam and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 181020A, which was also detected by Swift (Moss M. J. et al., GCN 23349, XRT: Goad M. R. et al., GCN 23351, BAT: Sakamoto T. et al., GCN 23357), Fermi (LAT: Axelsson M. et al., GCN 23350 and GBM: Veres P. et al., GCN 23352), and Konus-Wind (Tsvetkova A. et al., GCN 23363).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 19:00:40.500 UT. The measured peak count rate is 1000 cts/s above the background in combined data of four quadrants, with a total of 8409 cts. The local mean background count rate was 513.8 cts/s. Using cumulative rates, we measure a T90 of 19.4 s. In preliminary analysis, we find that 749 compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB181123B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23437
SUBJECT: GRB 181123B: Swift/UVOT Upper Limits
DATE:    18/11/23 15:38:28 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

GRB 181123B: Swift/UVOT Upper Limits

S. R. Oates (U.Warwick) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181123B
84 s after the BAT trigger (Lien et al., GCN Circ. 23432).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 23434)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC            84          233          147         >20.3
u_FC               296          546          246         >19.5
white               84         6529          727         >21.0
v                  626        10922         1228         >19.8
b                  551         6324          432         >20.1
u                  296         6119          659         >20.1
w1                4278        12566         1113         >20.2
m2                5509        11827         1082         >20.5
w2                5100         6734          393         >19.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181119A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23438
SUBJECT: GRB 181119A: AstroSat CZTI detection
DATE:    18/11/23 20:27:47 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 181119A, which was also detected by Insight-HXMT/HE detection (Yi Q. B. et al., GCN 23430).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 14:32:27.500 UT. The measured peak count rate is 350 cts/s above the background in combined data of four quadrants, with a total of 1971 cts. The local mean background count rate was 488 cts/s. Using cumulative rates, we measure a T90 of 19.6 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB181123B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23439
SUBJECT: GRB 181123B: Gemini-North optical detection
DATE:    18/11/23 20:30:11 GMT
FROM:    Wen-fai Fong at Northwestern U  <wfong@northwestern.edu>

W. Fong (Northwestern Univ.), N. R. Tanvir (U. Leicester) and A. J. Levan (U. Warwick) report on behalf of a larger collaboration:

"We observed the location of the short-duration GRB 181123B (Lien et al., GCN 23432) with the Gemini Multi-Object Spectrograph (GMOS) mounted on the Gemini-North 8-meter telescope. We obtained 18x90-sec each in the i-band at a mid-time of 2018 November 23.618 UT (9.2 hr post-burst). The observations have an airmass range of 1.4-1.9, 0.9â€ seeing, and were taken in thick, variable clouds. We detect a faint source consistent with the UVOT-enhanced XRT position (Evans et al., GCN 23433; Osborne et al., GCN 23434) at the position:

RA(J2000) = 12:17:27.95
Dec(J2000) = +14:35:52.5
+/- 0.05" in each coordinate

The source has a preliminary magnitude of i~23.32 +/- 0.25 AB mag, not corrected for Galactic extinction. Both astrometry and photometry are calibrated to SDSS. The source appears to be marginally extended; however, at present it is too weak of a detection to make a strong conclusion.

Further observations are planned. We thank the Gemini staff, and in particular observers Julia Scharwaechter and Michael Hoenig, for their assistance with these observations."


GRB_name: GRB181123B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23440
SUBJECT: GRB 181123B: Keck near-infrared imaging 
DATE:    18/11/23 20:53:41 GMT
FROM:    Wen-fai Fong at Northwestern U  <wfong@northwestern.edu>

K. Paterson and W. Fong (Northwestern) report:

"We observed the field of the short-duration GRB 181123B (Lien et al., GCN 23432) with the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) mounted on the 10-m Keck I telescope, starting on 2018 November 23 at 14:43:18 UT, 9.2 hours post-burst. We obtained 2100-sec of observations in the J-band in 1.0" seeing.

In our combined stack, we identify a near-IR source consistent with the X-ray position of the afterglow (Evans et al., GCN 23433; Osborne et al., GCN 23434) and the Gemini optical source (Fong et al., GCN 23439). Calibrated to 2MASS, we estimate a preliminary brightness of J(AB) = 22.94 +/- 0.19 mag. At this point it is not possible to tell whether this source is point-like or extended.

We thank the Keck Observatory staff, in particular Arina, Joel, Alessandro, Josh and Randy, for their assistance with planning and executing these observations."


GRB_name: GRB181123A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23442
SUBJECT: GRB 181123A, Swift-BAT refined analysis
DATE:    18/11/23 21:28:55 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 181123A (trigger #873178)
(Lien et al., GCN Circ. 23431).  The BAT ground-calculated position is
RA, Dec = 284.753, -8.208 deg which is
  RA(J2000)  =  18h 58m 36.2s
  Dec(J2000) = -08d 14' 14.3"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows some weak emission that starts at ~ T-60 s
and ends at ~T+190 s. T90 (15-350 keV) is 220.9 +- 55.9 sec (estimated error
including systematics).

The time-averaged spectrum from T-61.3 to T+187.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.88 +- 0.31.  The fluence in the 15-150 keV band is 9.9 +- 1.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-36.46 sec in the 15-150 keV band
is 0.3 +- 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/873178/BA/


GRB_name: GRB181123B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23443
SUBJECT: GRB 181123B: Swift-BAT lag analysis and search for extended emission 
DATE:    18/11/24 03:11:55 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. P. Norris (BSU), S. D. Barthelmy (GSFC), A. Y. Lien (GSFC/UMBC)
report:

We report the spectral lag analysis and the search for extended emission
for GRB 181123B (Lien et al., GCN Circ. 23432).

Using the 8-ms binned light curve, the spectral lag of the short pulse 
is 6 (+11, -11) ms for the 100-350 keV to 25-50 keV bands, and 10 (+14, -11) ms
for the 50-100 keV to 15-25 keV bands.  These lag values are consistent with 
a short GRB.

The Bayesian block analysis using the mask-tagged light curves suggests that 
there may be a marginal (~ 3 sigma) extended emission that lasts until ~T+60 s.


GRB_name: GRB181123B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23444
SUBJECT: GRB 181123B: Global MASTER Net optical inspection
DATE:    18/11/24 15:49:54 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov,  N.Tyurina, 
P.Balanutsa,A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institute

R. Podesta, F. Podesta, C. Lopez, C.Francile
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio 
(ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley,
South African Astronomical Observatory

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

O. Gres, N.M. Budnev, Yu.Ishmuhametova
Applied Physics Institute of Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk


MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru,
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in
Argentina (OAFA observatory of San Juan National University) was pointed 
to the  GRB181123B (Lien et al.,GCN 23432)  at 2018-11-23 
08:15:00 UT. On our 4-th (180s exposure)  set we  not found  optical 
transient within Swift error-box (ra=184.367 dec=14.5975 r=0.05) brighter 
than 17.0.


The galactic latitude b = -60 deg., longitude l = 98 deg.
The observations made on zenit distance = 32 deg.The moon ( 1 % bright
part) below the horizon (The altitude of the Moon is -44 deg. ).
The sun  altitude  is -50.0 deg.
The object can be observed till 2018-10-10 09:24:14


MASTER-Kislovodsk robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station 
of Pulkovo observatory) was pointed to the  GRB181123B (Lien et al., 
GCN 23432) 63194 sec after 
notice time and 63194 sec after trigger time at 2018-11-23 23:06:17 UT. On 
our 10-th (180s exposure)  set , obtained 72767 sec after tigger time at 
2018-11-24 01:45:51 UT, we  not found  optical transient within Swift 
error-box (ra=184.367 dec=14.5975 r=0.05) brighter than 18.1.

The galactic latitude b = 75 deg., longitude l = 272 deg.
The observations made on zenit distance = 53 deg.The moon (99 % bright 
part) is 34 deg. above the horizon. The distance between  moon and  object 
is 106
The sun  altitude  is -26.2 deg.
The object can be observed till sunrise at 2018-11-24 04:14:26


GRB_name: GRB181123A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23445
SUBJECT: Swift trigger 873178: GRB 181123A is Swift J1858.6-0814
DATE:    18/11/24 19:47:35 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. Greiner (MPE Garching), A. Y. Lien (GSFC/UMBC), and S. D. Barthelmy (GSFC)
report on behalf of the Swift team:

The location of Swift trigger 873178, which was previously identified as GRB 181123A
(Lien et al., GCN Circ. 23431 and 23442), is only 0.3 arcmin away from the XRT location
of the recently discovered transient, Swift J1858.6-0814 (Kennea et al. ATEL 12160;
Krimm et al., ATEL 12151). Therefore, we believe that the Swift trigger 873178 is
a flare from Swift J1858.6-0814, instead of a new GRB.

This flare is also seen in the BAT transient monitor (Krimm et al. 2013;
https://swift.gsfc.nasa.gov/results/transients/weak/SWIFTJ1858.6-0814/).


GRB_name: GRB181123A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23446
SUBJECT: Swift J1858.6-0814/GRB 181123A: Swift/BAT location correction to GCN 23442
DATE:    18/11/24 19:49:50 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC) reports on behalf of the Swift/BAT team:

In GCN Circ. 23442, the transient location was correct in sexadecimal units, 
but incorrect in the degree units. The correct degrees should be

RA: 284.6507   Dec: -8.2373 deg

We thank Jochen Greiner for noticing the error and we apologize for any confusion 
caused by this mistake.


GRB_name: GRB181121A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23447
SUBJECT: GRB 181121A: AstroSat CZTI detection
DATE:    18/11/25 01:24:18 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a short GRB 181121A, which was also detected by AGILE/MCAL detection (Ursi A. et al., GCN 23429).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 20:43:36.500 UT. The measured peak count rate is 1131.6 cts/s above the background in combined data of four quadrants, with a total of 1279 cts. The local mean background count rate was 477 cts/s. Using cumulative rates, we measure a T90 of 1.4 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB181125A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23448
SUBJECT: GRB 181125A: Swift detection of a burst
DATE:    18/11/25 09:07:44 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC),
P. D'Avanzo (INAF-OAB), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB)
and K. L. Page (U Leicester) report on behalf of the Neil Gehrels
Swift Observatory Team:

At 08:54:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181125A (trigger=873433).  Swift did not slew due to an
observing constraint.  The BAT on-board calculated location is 
RA, Dec 268.413, -2.613, which is 
   RA(J2000)  =  17h 53m 39s
   Dec(J2000) = -02d 36' 47"
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 10 sec.  The peak count rate
was ~1400 counts/sec (15-350 keV), at ~1 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 15:18 UT on 2019 January 31. There will thus be no XRT
or UVOT data for this trigger before this time. 

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


GRB_name: GRB181121A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23449
SUBJECT: IPN Triangulation of GRB 181121A (short)
DATE:    18/11/25 18:09:33 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and A. Ursi, N. Parmiggiani, F. Verrecchia, A. Bulgarelli,
A. Trois, M. Marisaldi, C. Pittori, M. Tavani, Y. Evangelista,
I. Donnarumma, M. Cardillo, G. Piano, G. Minervini, A. Argan,
F. Lucarelli, A. Zoli, V. Fioretti, F. Fuschino, M. Pilia,
F. Longo, A. Giuliani on behalf of the AGILE team report:

The short-duration GRB 181121A (Ursi et al., GCN Circ. 23429) was
detected by Konus-Wind, INTEGRAL (SPI-ACS), and AGILE (MCAL), at
about 74617 s UT (20:43:37).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
   14.424 (00h 57m 42s) -11.977 (-11d 58' 38")
 Corners:
   11.772 (00h 47m 05s)  -9.257 ( -9d 15' 24")
   13.883 (00h 55m 32s) -11.751 (-11d 45' 05")
   17.495 (01h 09m 59s) -14.686 (-14d 41' 10")
   14.969 (00h 59m 53s) -12.200 (-12d 12' 00")
 ---------------------------------------------
The error box area is 1.6 sq. deg, and its maximum
dimension is 7.8 deg (the minimum one is 29 arcmin).
The Sun distance was 126 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB181121_T74619/IPN

The time history and spectrum will be given in forthcoming
GCN Circulars.


GRB_name: GRB181125A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23450
SUBJECT: GRB 181125A: Swift-BAT refined analysis 
DATE:    18/11/25 18:25:06 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), E. Sonbas (Adiyaman Univ.),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-142 s to T+641 s (when the burst was in the BAT FOV)
from the recent telemetry downlink, we report further analysis of BAT GRB 181125A
(trigger #873433) (Sonbas et al., GCN Circ. 23448).
The BAT ground-calculated position is
RA, Dec = 268.391, -2.634 deg which is
  RA(J2000)  =  17h 53m 33.8s
  Dec(J2000) = -02d 38' 01.2"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 69%.

The mask-weighted light curve shows a single-peaked structure that starts
and peaks at ~T0, and ends at ~T+11 s. T90 (15-350 keV) is 10.5 +- 5.0 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.18 to T+11.24 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.57 +- 0.31.  The fluence in the 15-150 keV band is 3.3 +- 0.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.24 sec in the 15-150 keV band
is 1.5 +- 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/873433/BA/


GRB_name: GRB181125A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23451
SUBJECT: GRB 181125A: Fermi GBM observation
DATE:    18/11/25 19:15:25 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:


"At 08:54:41.73 UT on 25 November 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181125A (trigger 564828886 / 181125371),
which was also detected by the Swift-BAT (Sonbas et al. 2018, GCN 23448).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 64 degrees.

The GBM light curve shows a structured emission
with a duration (T90) of about 4 s (50-300 keV).
The time-averaged spectrum from T0-1.8 s to T0+2 s is
adequately fit by a simple power law function
with index -1.8 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(4.3 +/- 0.10)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-1.15 s in the 10-1000 keV band
is 2.0 +/- 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: GRB181123B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23452
SUBJECT: GRB 181123B: Insight-HXMT/HE detection
DATE:    18/11/26 06:54:25 GMT
FROM:    QiBin Yi at IHEP, HXMT  <yiqb@ihep.ac.cn>

Q. B. Yi, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2018-11-23T05:33:03.09 (T0), the Insight-HXMT/HE detected 
GRB 181123B (trigger ID: HEB181123231) in a routine search of the data,
which was also detected by the SWIFT/BAT (J. P. Norris et al. 2018, GCN 23443)

The Insight-HXMT/HE light curve mainly consists of a 
pulse with a duration (T90) of 0.23 s measured from T0+0.16 s. 
The 50-ms peak rate, measured from T0+0.28 s, is 5091.4 cnts/s. 
The total counts from this burst is 2060.5 counts. 
URL_LC:  http://www.hxmt.org/images/GRB/HEB181123231_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB181126A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23453
SUBJECT: GRB 181126A: Swift detection of a burst
DATE:    18/11/26 10:05:09 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC),
P. D'Avanzo (INAF-OAB), N. P. M. Kuin (UCL-MSSL),
A. Melandri (INAF-OAB), K. L. Page (U Leicester) and
M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 09:54:08 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181126A (trigger=873539).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 152.351, -29.679, which is 
   RA(J2000)  =  10h 09m 24s
   Dec(J2000) = -29d 40' 43"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two peaks
with a total duration of about 2 sec.  The peak count rate
was ~5500 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 09:55:23.1 UT, 75.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 152.34775, -29.68611 which is
equivalent to:
   RA(J2000)  = 10h 09m 23.46s
   Dec(J2000) = -29d 41' 10.0"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 27 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 79 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
0.07. 

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


GRB_name: GRB181126A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23454
SUBJECT: GRB 181126A: Prompt enhanced Swift-XRT position
DATE:    18/11/26 10:23:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using  promptly downlinked XRT event data for GRB 181126A, we find an
enhanced XRT position of the afterglow: RA, Dec: 152.3477, -29.6875
which is equivalent to:
   RA (J2000)  = 10 09 23.46
   Dec (J2000) = -29 41 15.0
with an uncertainty of 2.5 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/873539.

Position enhancement is 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: GRB181126A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23455
SUBJECT: GRB 181126A: Enhanced Swift-XRT position
DATE:    18/11/26 11:47:27 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 804 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 181126A, 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 = 152.34848, -29.68747 which is equivalent
to:

RA (J2000): 10h 09m 23.64s
Dec (J2000): -29d 41' 14.9"

with an uncertainty of 2.3 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: GRB181121A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23456
SUBJECT: Konus-Wind observation of GRB 181121A
DATE:    18/11/26 14:55:41 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 181121A
(AGILE/MCAL detection: Ursi et al., GCN 23429;
AstroSat CZTI detection: Sharma et al., GCN 23447;
IPN Triangulation: Kozlova et al., GCN 23449)
triggered Konus-Wind at T0=74619.153 s UT (20:43:39.153).

The burst light curve shows a multipeaked structure
which starts at ~T0 s and has a total duration of ~1.4 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.46(-0.26,+0.44)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.118 s,
of 9.44(-1.53,+1.77)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.83(-0.20,+0.46),
the high energy photon index beta = -2.58(-1.04,+0.46),
the peak energy Ep = 226(-65,+45) keV
(chi2 = 72/56 dof).

The spectrum near the maximum count rate
(measured from T0+0.064 to T0+0.192 s)
is best fit in the 20 keV - 2 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.27(-0.24,+0.32),
the high energy photon index beta = -2.54(-0.47,+0.28),
the peak energy Ep = 271(-47,+50) keV
(chi2 = 57/42 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181121_T74619/

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


GRB_name: GRB181126A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23457
SUBJECT: GRB 181126A: Fermi GBM observation
DATE:    18/11/26 17:46:16 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari)
reports on behalf of the Fermi GBM Team:


"At 09:54:09.94 UT on 26 November 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181126A (trigger 564918854/ 181126413),
which was also detected by the Swift-BAT (Sonbas et al. 2018, GCN 23453).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi-LAT boresight
at the GBM trigger time is 111 degrees.

The GBM light curve consists of bright single pulse
with a duration (T90) of about 0.6 s (50-300 keV).
The time-averaged spectrum from T0-0.1 s to T0+0.4 s is
adequately fit by a Band function with Epeak = 90 +/- 25 keV,
alpha = -0.1 +/- 0.6, and beta = -2.1 +/- 0.2.

The event fluence (10-1000 keV) in this time interval is
(4.8 +/- 0.5)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-64 ms in the 10-1000 keV band
is 10.5 +/- 1.7 ph/s/cm^2.


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


GRB_name: GRB181126A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23458
SUBJECT: GRB 181126A deep Gemini imaging
DATE:    18/11/26 19:45:59 GMT
FROM:    Nial Tanvir at U.Leicester  <nrt3@star.le.ac.uk>

N. R. Tanvir (U. Leicester) and W. Fong (Northwestern Univ.)
report on behalf of a larger collaboration:

We observed the field of Swift GRB 181126A (Sonbas et al.
GCN 23453) with the Gemini North telescope on Mauna Kea,
beginning 2018-11-26 14:11 UT, approximately 4.3 hr post-burst.
Images were obtained in the z filter using GMOS-N with total
exposure of 15x60s.

No credible afterglow is visible at the revised X-ray position
(Beardmore et al. GCN 23455) to a 3-sigma magnitude z(AB)=25.4,
uncorrected for Galactic extinction.

We thank Mirko Simunovic and Christy Cunningham for
efficiently executing these observations.


GRB_name: GRB181126A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23459
SUBJECT: GRB 181126A: Swift-XRT refined Analysis
DATE:    18/11/26 21:26:30 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea
(PSU) and E. Sonbas report on behalf of the Swift-XRT team:

We have analysed 9.3 ks of XRT data for GRB 181126A (Sonbas et al. GCN
Circ. 23453), from 82 s to 29.9 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. 23454).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.95 (+/-0.09).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.7 (+0.8, -0.6). The
best-fitting absorption column is  9.7 (+6.5, -4.2) x 10^21 cm^-2, in
excess of the Galactic value of 8.1 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.3 x 10^-11 (1.2 x 10^-10) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      9.7 (+6.5, -4.2) x 10^21 cm^-2
Galactic foreground: 8.1 x 10^20 cm^-2
Excess significance: 3.4 sigma
Photon index:      2.7 (+0.8, -0.6)

If the light curve continues to decay with a power-law decay index of
0.95, the count rate at T+24 hours will be 9.5 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.2 x
10^-14 (1.1 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/00873539.

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


GRB_name: GRB181126A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23460
SUBJECT: GRB 181126A: Swift/UVOT Upper Limits
DATE:    18/11/26 22:14:48 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181126A
80s after the BAT trigger (Sonbas et al., GCN Circ. 23453).
No optical afterglow consistent with the XRT position (Beardmore et al.,
GCN Circ. 23455) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding
chart (FC) exposure and subsequent exposures are:

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

white_FC            80          230          147         >20.4
white               80         1181          342         >20.5
v                  622         1069           58         >18.0
b                 1147         1167           20         >18.2
u                  292         1142          285         >20.1
w1                 671         1118           58         >20.2
m2                 646         1093           58         >19.0
w2                 597         1044           58         >18.4

The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.07 in the direction of the
burst (Schlegel et al. 1998).


GRB_name: GRB181123B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23461
SUBJECT: GRB 181123B: Keck further near-infrared imaging
DATE:    18/11/27 01:09:10 GMT
FROM:    Kerry Paterson at North Western U.  <kerry.paterson@northwestern.edu>

K. Paterson, W. Fong (Northwestern), K. De (Caltech), K. Alexander, D. Coppejans, A. Hajela, R. Margutti, and G. Terreran (Northwestern) report:

"We observed the field of the short-duration GRB 181123B (Lien et al., GCN 23432) with the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) mounted on the 10-m Keck I telescope, starting on 2018 November 26 at 14:57:43 UT, 1.94 days after our previous MOSFIRE observations (Paterson et al. GCN 23440) and 3.38 days after the burst. We obtained 2142-sec of observations in the J-band in 0.7" seeing and clear conditions.

We detect a NIR source that is clearly extended, with a brightness and position consistent with our previous observations (Paterson et al. GCN 23440) and with the Gemini optical source position (Fong et al. GCN 23439). Image subtraction between our MOSFIRE observations also yields no residuals in or around the XRT position (Evans et al. GCN 23433; Osborne et al. GCN 23434) or the position of the optical source. Given the lack of residuals and the extended nature of the NIR source, we propose this as the host galaxy of GRB 181123B. We also place a 3-sigma upper limit of J>23.3 mag (AB, for epoch 1 at 9.2 hr post-burst) on afterglow emission from GRB 181123B.

We thank the Keck staff for their assistance with these ToO observations."


GRB_name: GRB181126A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23462
SUBJECT: GRB 181126A: No Ks-band afterglow detection with Keck I
DATE:    18/11/27 01:41:58 GMT
FROM:    Kishalay De at Caltech, GROWTH  <kde@astro.caltech.edu>

K. De (Caltech) reports on behalf of a larger collaboration

At 2018-11-26 14:13 UT, 4.32 hours after GRB 181126A (GCN 23453), we observed the location of the XRT counterpart (GCN 23455) with the MOSFIRE instrument on the Keck I telescope. With a total exposure time of 416 seconds, no afterglow is detected to a 3-sigma Ks-band limit of 23.6 AB mag.


GRB_name: GRB181126A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23463
SUBJECT: GRB 181126A: Swift-BAT refined analysis
DATE:    18/11/27 03:41:42 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), J. P. Norris (BSU),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.),
T. N. Ukwatta (LANL) (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 181126A (trigger #873539)
(Sonbas et al., GCN Circ. 23453).  The BAT ground-calculated position is
RA, Dec = 152.350, -29.698 deg which is
  RA(J2000)  =  10h 09m 24.0s
  Dec(J2000) = -29d 41' 52.9"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 68%.

The mask-weighted light curve shows two short pulses. The first pulse starts
at ~ T-0.1 s, peaks at ~T0, and ends at ~T+0.2 s. The second pulse starts
at ~T+1.6 s, peaks at ~T+1.8 s, and ends at ~T+2.2 s. T90 (15-350 keV) is
2.09 +- 0.12 sec (estimated error including systematics).

The time-averaged spectrum from T-0.07 to T+2.16 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index -0.13 +- 0.75,
and Epeak of 83.8 +- 24.2 keV (chi squared 66.64 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 3.1 +- 0.4 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T+1.22 sec in the 15-150 keV band is
2.7 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.22 +- 0.15 (chi squared 79.71 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level.

Using the 8-ms binned light curve, the spectral lag for the 100-350 keV to
25-50 keV bands is 26 (+19, -15) ms for the first pulse, and 10 (+21, -13) ms
for the second pulse. These lag values are intermediate between short and
long GRBs, but also are consistent with short GRBs when considering the
large error bars. In addition, no extended emission is found.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/873539/BA/


GRB_name: GRB181127A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23465
SUBJECT: GRB 181127A : a long GRB detected by INTEGRAL
DATE:    18/11/27 10:36:54 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro.mereghetti@inaf.it>

S.Mereghetti (INAF, IASF-Milano), D.Gotz (CEA, Saclay),  C.Ferrigno,
E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC,
Versoix) and J.Borkowski (CAMK, Torun) report:

a gamma ray burst lasting about 15 s has been detected by IBAS in the
IBIS/ISGRI data at 06:46:20  UT of November 27, 2018. The burst was
detected  with a significance below the threshold for  automatic alert
delivery (IBAS Weak Alert n.8167 was distributed at
06:46:50 UT).

The refined coordinates (J2000) are:

R.A.=  285.3433 deg
DEC.=   31.6895 deg

with an uncertainty of  2.5   arcmin (90% c.l.).

The burst had a peak flux of  0.5    counts/cm2/s (20-200 keV, 1-s
integration  time) and a fluence in the same energy range of about 4e-7
erg/cmq.

A plot of the light curve is posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html


GRB_name: GRB181123B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23467
SUBJECT: GRB 181123B: ATCA 5/9 GHz rapid-response radio observation
DATE:    18/11/28 01:16:17 GMT
FROM:    Gemma Anderson at Curtin U  <gemma.anderson@curtin.edu.au>

G. E. Anderson (Curtin), M. E. Bell (UTS), J. Stevens (CASS), P. J. Hancock (Curtin),
J. C. A. Miller-Jones (Curtin), A. Bahramian (Curtin), K. W. Bannister (CASS),
A. J, van der Horst (GWU), S. D. Ryder (Macquarie), J-P. Macquart (Curtin),
R. M. Plotkin (Curtin), A. Rowlinson (UvA)

We used the Australia Telescope Compact Array (ATCA) rapid-response mode
to perform a triggered radio observation of the short GRB 181123B. The ATCA
responded to the Swift-BAT detection (Lien et al., GCN 23432), automatically
scheduling observations to begin on 2018 Nov 23.753 UT for 8.5 hours
(12.5 hours post-burst), when the GRB had risen above the horizon. No radio
source was detected at the XRT/optical position (Evans et al., GCN 23433,
Fong et al., GCN 23439), with 3 sigma upper-limits of 66 microJy and 69 microJy
at 5 and 9 GHz, respectively.

We thank the ATCA and CSIRO Astronomy and Space Science (CASS) staff for
supporting this new mode of operation.


GRB_name: GRB181119A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23468
SUBJECT: GRB 181119A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/11/30 17:11:35 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

T. Sakamoto, A. Yoshida, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:


The long GRB 181119A (Insight-HXMT/HE detection: Yi et al., GCN Circ. 23430;
AstroSat CZTI detection: Sharma et al., GCN Circ. 23438) triggered
the CALET Gamma-ray Burst Monitor (CGBM) at 14:32:16.825 UTC
on 19 November 2018. The burst signal was seen by all CGBM detectors.

The burst light curve shows three main peaks which start at T+0.3 sec and
end at T+15.8 sec. The T90 and the T50 durations measured by the SGM 
data are
15.0 +- 0.4 sec and 8.1 +- 3.2 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1226673130/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.


GRB_name: GRB181201A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23469
SUBJECT: GRB 181201A: a long GRB detected by INTEGRAL
DATE:    18/12/01 03:43:01 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro.mereghetti@inaf.it>

S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay),  C.Ferrigno, E.Bozzo,
V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix)
and J.Borkowski (CAMK, Torun) report:

a gamma ray burst lasting about 180 s has been detected by IBAS in the
IBIS/ISGRI data at   02:38 UT of 1 December 2018

The refined coordinates (J2000) are:

R.A.=  319.3009 deg
DEC.= -12.6242  deg

with an uncertainty of   2  arcmin (90% c.l.).

The burst was bright and saturated the telemetry. Therefore, we can only
give lower limits to its  peak flux of greater than 2  counts/cm2/s (20-200
keV, 1-s integration
time) and a fluence in the same energy range of more than 1e-4  erg/cmq.

A plot of the light curve will  be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23470
SUBJECT: GRB 181201A MASTER-Net OT detection
DATE:    18/12/01 10:15:47 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa,
A.Kuznetsov, V.V.Chazov, A.V. Krylov, I. Gorbunov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

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

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

K. Ivanov, O. Gres, N.M. Budnev, S.Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov 
et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA 
observatory of San Juan National University) was pointed to the  GRB181201.11 
10 sec after notice time and 18 sec after trigger time at 2018-12-01 02:40:30 
UT. On our first (10s exposure)  set we  found 1 optical transient within 
INTEGRAL error-box (ra=319.317 dec=-12.6325 r=0.05) brighter than 16.2.


  T-Tmid      Date      Time       Expt.        Ra                Dec      Mag
-------|---------------------|-------|-----------------|-----------------|------
     23   2018-12-01 02:40:30      10   ( 21h 17m 11.2s , -12d 37m 51.4s) |13.17

The 5-sigma upper limit has been about 16.2mag
The message may be cited.


====================================================================


The galactic latitude b = -39 deg., longitude l = 39 deg.
The observations made on zenit distance = 76 deg.The moon (38 % bright part) 
below the horizon (The altitude of the Moon is -41 deg. ).
The sun  altitude  is -30.9 deg.
The object can be observed till 2018-12-01 03:49:27


GRB_name: GRB181201A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23471
SUBJECT: GRB 181201A: likely Swift/XRT afterglow
DATE:    18/12/01 10:23:45 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro.mereghetti@inaf.it>

S.Mereghetti, F.Pintore (IASF-Milano), D.Gotz (CEA, Saclay),
C.Ferrigno, E.Bozzo,
V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix)
and J.Borkowski (CAMK, Torun) report:

The Swift XRT observed the position of GRB181201A starting 4 hr after the
INTEGRAL trigger time, from 6:33 UT to 7:06 UT.
A possibly fading X-ray source with count rate of 2.38+/-0.04 ct/s is
detected inside the IBAS error circle at coordinates
R.A. = 21 17 11
Dec.= -12 37 48

[GCN OPS NOTE(01dec18): Per author's request, indentification name of the burst
was changed from "GRB 180112A" to "GRB 181201A" in both the SUBJECT line
and in the first sentence of the circular.]


GRB_name: GRB181201A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23472
SUBJECT: GRB 181201A: Swift-XRT afterglow
DATE:    18/12/01 12:12:37 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro.mereghetti@inaf.it>

F.Pintore, S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay),  C.Ferrigno,
E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC,
Versoix)
and J.Borkowski (CAMK, Torun) report:

Swift/XRT observed the position of GRB181201A on 1 December 2018 from 6:33
UT to 7:06 UT (GCN #23471), in PC mode.

The XRT data show that the X-ray source reported by Mereghetti et al. (GCN
Circ. n. 23471 ) is fading and has  an average spectrum well modelled by a
single absorbed powerlaw. The best-fit parameters are: column density of (6
+\- 2)x10^20 cm-2, consistent with the Galactic column density (5.2e20
cm-2, Willingale et al.2013),  photon index of 1.76 +\- 0.08. The average
0.3-10 keV absorbed flux is (1.06 +\- 0.06)x10^-10 erg cm-2 s-1.

The time decay is well modeled with a power law of index 1.2 +\- 0.1


GRB_name: GRB181201A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23473
SUBJECT: GRB 181201A: Swift ToO observations
DATE:    18/12/01 13:45:27 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the INTEGRAL GRB 181201A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020848

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the INTEGRAL event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB181201A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23474
SUBJECT: GRB 181201A: Swift-XRT afterglow detection
DATE:    18/12/01 14:17:02 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia
(ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), S. J. LaPorte
(PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU) and P.A. Evans
(U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the INTEGRAL-detected
burst GRB 181201A (Mereghetti et al. GCN Circ. 23469), collecting 5.0
ks of Photon Counting (PC) mode data between T0+14.3 ks and T0+26.4 ks.


Five uncatalogued X-ray sources are detected, of which one ("Source 5")
is above the RASS limit, and is therefore likely the GRB afterglow.
Using 4968 s of PC mode data and 3 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 = 319.29666, -12.63082 which is
equivalent to:

RA (J2000): 21h 17m 11.20s
Dec(J2000): -12d 37' 51.0"

with an uncertainty of 2.0 arcsec (radius, 90% confidence). This
position is 28 arcsec from the INTEGRAL position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.44 (+/-0.18).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.74 (+0.08, -0.07). The
best-fitting absorption column is  6.1 (+2.0, -0.9) x 10^20 cm^-2,
consistent with the Galactic value of 5.2 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.8 x 10^-11 (4.2 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.1 (+2.0, -0.9) x 10^20 cm^-2
Galactic foreground: 5.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.74 (+0.08, -0.07)

If the light curve continues to decay with a power-law decay index of
1.44, the count rate at T+24 hours will be 0.30 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-11 (1.3 x 10^-11) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020848.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020848.

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


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23475
SUBJECT: GRB 181201A: iTelescope optical afterglow detection
DATE:    18/12/01 15:48:16 GMT
FROM:    Albert Kong at NTHU  <akhkong@gmail.com>

A.K.H. Kong (NTHU, Taiwan)

We observed the field of GRB 181201A (Mereghetti et al. GCN 23469)
with the T31 0.5m telescope of iTelescope.Net in Siding Spring,
Australia. The observation was done with the R-band filter beginning
at 2018-12-01 10:56:18 UT (8.3 hours after the INTEGRAL trigger) for
300 sec. At the position of the Swift X-ray afterglow (Mereghetti et
al. GCN 23471; Page et al. GCN 23474), an optical transient is clearly
detected with a R magnitude of 16.68 +/- 0.03 by comparing with the
USNO-B1 catalogue. The position is also consistent with the optical
transient detected by Podesta et al. (GCN 23470) 18 sec after the
trigger. Given the fading of the optical brightness, this transient is
the optical afterglow of GRB 181201A.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23476
SUBJECT: GRB 181201A MASTER-Net OT continued observation
DATE:    18/12/01 17:24:28 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, 
P.Balanutsa,
A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

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

K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory

MASTER-Kislovodsk robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station 
of Pulkovo observatory) was pointed to the  GRB181201A (Mereghetti et 
al., GCN #23469) ~13.3 hours after trigger time at 2018-12-01 15:57:35 UT.
On our first (180s exposure)  set we  found  optical transient detected 
by MASTER-OAFA (Podesta et al,  GCN 23470; Gorbovskoy et al., Atel 
#12255; also observed by Kong GCN #23475;).


  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
  47915s   2018-12-01 15:57:35     180    (21h 17m 11.11s , -12d 37m 50.9s)    17.6

The 5-sigma upper limit has been about 18.3 mag


The galactic latitude b = -39 deg., longitude l = 39 deg.
The observations made on zenit distance = 64 deg.The moon (32 % bright 
part) below the horizon (The altitude of the Moon is -41 deg. ).
The sun  altitude  is -25.6 deg.
The object can be observed till sunrise at 2018-12-02 04:21:42 UT.

The message may be cited.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23477
SUBJECT: GRB 181201A: optical observations in SAAO
DATE:    18/12/01 20:06:16 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), E. Mazaeva (IKI), D. Buckley (SAAO), A. Pozanenko 
(IKI)  report on behalf of IKI-FuN follow-up collaboration:

We observed  the field of the INTEGRAL GRB 181201A  (Mereghetti et al., 
GCN  23469)  with 1m telescopes of SAOO observatory. Observation started 
on Dec. 01 (UT) 18:34:35 in g'Ri'-filters.  We detected optical 
afterglow  (Podesta et al., GCN  23470; Kong  GCN 23475). Preliminary 
photometry   is following

Date       UT start t-T0    Filter Exp.   OT    Err.
                     (mid, days)    (s)

2018-12-01 18:34:35 0.66950  g'     5*180 17.86 0.02
2018-12-01 18:52:05 0.67992  R      5*120 17.38 0.02
2018-12-01 19:02:35 0.68721  i'     5*120 17.32 0.02

The photometry is based on  SDSS DR12 nearby stars.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23478
SUBJECT: GRB 181201A: NOT optical observations
DATE:    18/12/01 21:41:15 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI  <keh14@hi.is>

Kasper E. Heintz (Univ. of Iceland), Daniele B. Malesani (DAWN/NBI and DARK/NBI), and Shane Moran-Kelly (Univ. of Turku and NOT), report on behalf of a larger collaboration:

We observed the optical afterglow (Podesta et al., GCN  23470; Kong, GCN 23475; Lipunov et al., GCN 23476: Volnova et al., GCN 23477) of the INTEGRAL GRB 181201A (Mereghetti et al., GCN 23469) with the 2.5-m Nordic Optical Telescope (NOT) equipped with StanCam.

Observations were carried out in the Bessel R filter, but calibrated against SDSS r-band Pan-STARRS local photometry, corrected to the R-band using the Lupton transformation. At a mid-time of 20:27:09 UT on December 1 (i.e. 17.8 hr after trigger) we measure for the optical counterpart: r = 17.5 +/- 0.1 AB mag, where the error is dominated by scatter in the preliminary calibration.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23479
SUBJECT: GRB 181201A: Zeiss-1000/CrAO optical observations
DATE:    18/12/01 23:21:37 GMT
FROM:    Alina Volnova at SAI MSU  <alinusss@gmail.com>

E. Mazaeva (IKI), A. Volnova (IKI), A. Pozanenko (IKI), I. Nikolenko
(CrAO),
A. Novichonok (KIAM, PetrSU), I. Molotov (KIAM)
report on behalf of larger GRB follow-up collaboration:

We observed the field of the INTEGRAL GRB 181201A (Mereghetti et al.,
GCN 23469) with Zeiss-1000/Koshka (CrAO) telescope starting Dec 01,
16:55:28 UT. We obtained several frames in R filter. The optical
afterglow (Podesta et al., GCN  23470; Kong, GCN 23475) is clearly
detected in the stacked frame. Preliminary photometry is following:

Date             UT start   t-T0            Filter   Exp.     OT      Err.
                                   (mid, days)            (s)
2018-12-01 16:55:28  0.60359      R        23*60   17.17   0.05

The photometry is based on  SDSS DR12 nearby stars.


GRB_name: GRB181201A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23480
SUBJECT: GRB 181201A: Fermi-LAT detection
DATE:    18/12/02 02:41:40 GMT
FROM:    Magnus Axelsson at Stockholm U.  <magaxe@kth.se>

M. Arimoto (Kanazawa U.), M. Axelsson (KTH & Stockholm Univ.), and M. Ohno (Hiroshma U.) report on behalf of the Fermi-LAT team:

On December, 01, 2018, Fermi-LAT detected high-energy emission from GRB 181201A, which was also detected by INTEGRAL (Mereghetti et al., GCN 23469) and Swift/XRT (Pintore et al., GCN 23472).

The best LAT on-ground location is found to be

RA, Dec = 319.28, -12.60 (degrees, J2000)

with an error radius of 0.06 deg (90% containment, statistical error only).
This was 131 deg from the LAT boresight at the time of the INTEGRAL trigger:

T0 =  02:38:00 UT

and entered the LAT field of view ~2000 seconds later.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially correlated with the INTEGRAL source (0.03 degrees from the INTEGRAL location) with high significance. The photon flux above 100 MeV in the time interval 2000-10000 s after the INTEGRAL trigger is (4.5 +/- 3.3) E-7 ph/cm2/s.

The estimated photon index above 100 MeV is -1.32+/-0.39.

The highest-energy photon is a 25.5 GeV event which is observed ~7600 seconds after the INTEGRAL trigger.

The Fermi-LAT point of contact for this burst is Masanori Ohno (ohno@astro.hiroshima-u.ac.jp<mailto:ohno@astro.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: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23481
SUBJECT: GRB 181201A: COATLI Optical Detection
DATE:    18/12/02 06:37:42 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Margarita Pereyra (UNAM), Nat Butler (ASU), Rosa
L. Becerra (UNAM), William H. Lee (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM),
Alexander Kutyrev (GSFC), and Eleonora Troja (GSFC), report:

We observed the field of GRB 181201A (Mereghetti et al., GCN 23469) with
the COATLI 50-cm telescope and interim imager at the Observatorio
AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir
(http://coatli.astroscu.unam.mx) from 2018-12-02 01:39:01 to 04:02:58
(from 23.0 to 25.4 hours after the trigger), obtaining a total of 1.89
hours of exposure in the w filter.

We detect the optical counterpart reported by Podesta et al. (GCN Circ.
23470) at w = 17.82 +/- 0.01.

Our w magnitudes are calibrated against the USNO-B1 catalog (adjusted to
an approximate AB system) and are not corrected for Galactic extinction
in the direction of the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB181202A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23482
SUBJECT: GRB 181202A: Swift detection of a burst with an optical counterpart
DATE:    18/12/02 06:48:16 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J. K. Cannizzo (NASA/UMBC), J.D. Gropp (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 06:36:24 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181202A (trigger=874334).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 280.745, +27.951 which is 
   RA(J2000) = 18h 42m 59s
   Dec(J2000) = +27d 57' 03"
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 10 sec.  The peak count rate
was ~1100 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 06:37:49.8 UT, 85.4 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 280.73563, 27.95894 which is equivalent
to:
   RA(J2000)  = 18h 42m 56.55s
   Dec(J2000) = +27d 57' 32.2"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 41 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 1.67
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting 86
seconds after the BAT trigger. There is a candidate afterglow in the rapidly
available 2.7'x2.7' sub-image at
  RA(J2000)  = 18:42:56.38 = 280.73490
  DEC(J2000) = +27:57:35.0  =  27.95973
with a 90%-confidence error radius of about 0.63 arc sec. This position is 3.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.67 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 J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB181202A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23483
SUBJECT: GRB 181202A: Enhanced Swift-XRT position
DATE:    18/12/02 09:14:27 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1454 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 181202A, 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 = 280.73491, +27.95964 which is equivalent
to:

RA (J2000): 18h 42m 56.38s
Dec (J2000): +27d 57' 34.7"

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: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23484
SUBJECT: GRB 181201A: Global MASTER-Net prompt optical descovery and afterglow observations
DATE:    18/12/02 10:26:59 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa,
A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

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

K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory


MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Argentina (OAFA observatory of San Juan National University) was pointed 
to the INTEGRAL  GRB181201A ((Mereghetti et
al., GCN #23469) 10 sec after notice time and 18 sec 
after trigger time at 2018-12-01 02:40:30 UT. We discovered prompt  growing (one mag per 
minute) optical flash MASTER OT J211711.20-123751.4
(Podesta et al., GCN #23470; Gorbovskoy et al., Atel #12255) at RA,Dec  = 
21h 17m 11.20s -12d 37m 51.4s


Later we observed afterglow at MASTER-Kislovodsk (Lipunov et al., #23476), 
MASTER-SAAO, MASTER-IAC and MASTER-OAFA against in B,V,R,I and Clear fiters.
Observations are continuated.

This message can be cited.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23485
SUBJECT: GRB 181201A: optical observations in Chilescope observatory
DATE:    18/12/02 13:19:51 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), E. Mazaeva (IKI), A. Volnova (IKI), 
M. Krugov (AFIF) report on behalf of IKI-FuN follow-up collaboration:

We observed  the field of the INTEGRAL GRB 181201A  (Mereghetti et al.,
GCN  23469)  with RC-1000 telescope of CHILESCOPE observatory. 
Observations started on Dec. 02 (UT) 01:11:25 in r'-filter.  We detected 
optical afterglow  (e.g. Podesta et al., GCN  23470; Kong, GCN 23475; 
Lipunov et al., GCN 23476: Volnova et al., GCN 23477; Heintz et al., GCN 
23478; Mazaeva et al., GCN 23479). Preliminary photometry   is following.

Date       UT start t-T0    Filter Exp.   OT    Err.
                     (mid, days)    (s)

2018-12-02 01:11:25 0.9416  r'     300    18.00  0.05

The photometry is based on the SDSS DR12 star

SDSS-DR12_id        r
J211710.81-123706.3 16.517


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23486
SUBJECT: GRB 181201A: GROND detection of the afterglow and redshift upper limit of z < 3
DATE:    18/12/02 15:19:53 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan@bolmer.de>

J. Bolmer (MPE, Garching) and P. Schady (Univ. of Bath) report:

We observed the field of GRB 181201A (INTEGRAL trigger; Mereghetti et al., GCN #23469)
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted
at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).

Observations started at 00:16 UT, 21.85 hrs after the GRB trigger, and were performed
under good seeing conditions, 1.03'', and at an average airmass of 1.43.

We detect a source at a position consistent with the X-ray and optical afterglow
(Page et al., GCN #23474; Podesta et al., GCN #23470; Heintz et al., GCN #23478).
Based on the first 17 min of total exposures in g'r'i'z' and 20 min in JHK, we
measure the following preliminary AB magnitudes:

g' = 18.14 +/- 0.03 mag
r' = 17.97 +/- 0.03 mag
i' = 17.80 +/- 0.03 mag
z' = 17.64 +/- 0.03 mag
J = 17.55 +/- 0.05 mag
H = 17.28 +/- 0.05 mag
K = 17.13 +/- 0.08 mag

Given magnitudes are calibrated against SDSS and 2MASS field stars and
are not corrected for the expected Galactic foreground extinction corresponding
to a reddening of E_(B-V)=0.05 in the direction of the burst (Schlafly &
Finkbeiner 2011).

From a fit to the SED with a simple powerlaw including SMC-like dust
extinction and a model for absoprtion from the Lyman-alpha forest we
determine an upper limit for the redshift of z < 3 and  A_V < 0.10 mag.
The powerlaw index is -0.50.


GRB_name: GRB181202A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23487
SUBJECT: GRB 181202A: Swift-XRT refined Analysis
DATE:    18/12/02 16:46:15 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U. Leicester), J.P.
Osborne (U. Leicester) and J.K. Cannizzo report on behalf of the
Swift-XRT team:

We have analysed 7.0 ks of XRT data for GRB 181202A (Cannizzo et al.
GCN Circ. 23482), from 102 s to 29.4 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. 23483).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.86 (+/-0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.69 (+0.22, -0.17). The
best-fitting absorption column is  1.93 (+0.97, -0.26) x 10^21 cm^-2,
consistent with the Galactic value of 1.7 x 10^21 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 4.2 x 10^-11 (5.1 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.93 (+0.97, -0.26) x 10^21 cm^-2
Galactic foreground: 1.7 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.69 (+0.22, -0.17)

If the light curve continues to decay with a power-law decay index of
0.86, the count rate at T+24 hours will be 3.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x
10^-13 (1.8 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/00874334.

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


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23488
SUBJECT: GRB 181201A: VLT/FORS2 tentative spectroscopic redshift
DATE:    18/12/02 16:53:48 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

L. Izzo, A. de Ugarte Postigo, D. A. Kann (all HETH/IAA-CSIC), D. B. 
Malesani (DAWN/NBI/DTU and DARK/NBI), K. E. Heintz (Univ. of Iceland), 
N. R. Tanvir (Univ. Leicester), V. D'Elia (SSDC), K. Wiersema (Univ. 
Warwick), C. Kouveliotou (GWU), and A. J. Levan (Univ. Warwick) report 
on behalf of the Stargate collaboration:

We observed the optical counterpart (Podesta et al., GCN #23470; Kong, 
GCN #23475; Lipunov et al., GCN #23476; Volnova et al., GCN #23477; 
Heintz et al., GCN #23478; Mazaeva et al., GCN #23479; Watson et al., 
GCN #23481; Belkin et al., GCN #23485; Bolmer & Schady, GCN #23486) of 
the long, very bright INTEGRAL GRB 181201A (Mereghetti et al., GCN 
#23469) with the ESO VLT UT1 equipped with the FORS2 spectrograph. We 
obtained a single 600 s spectrum in the low-resolution grism 300V. 
Observations started at 00:50:50 UT on December 2 (i.e., 22.16 hr after 
trigger).

In the spectrum, the continuum is detected at excellent signal-to-noise 
but is largely featureless. From a non-detection of any break in the 
continuum down to 3500 Ã…, we derive a redshift upper limit of z < 1.88. 
There are no strong lines visible, but we note the possible presence of 
three weak lines, which, if real, can be identified as the Mg II doublet 
and Mg I, implying a redshift of z = 0.450. No emission lines are 
visible. Pan-STARRS archive imaging (Chambers et al. 2016, 
arXiv:1612.05560) shows the presence of a possible host galaxy at i' ~ 
23.4 mag.

We acknowledge the ESO observing staff at Paranal, especially Cedric 
Ledoux, Joe Anderson, and Rodrigo Tomero. We are also indebted to the 
ESPRESSO commissioning team who kindly granted us permission to carry 
out this ToO observation during their time.


GRB_name: GRB181202A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23489
SUBJECT: GRB 181202A: Swift-BAT refined analysis
DATE:    18/12/02 23:49:59 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. K. Cannizzo (NASA/UMBC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 181202A (trigger #874334)
(Cannizzo et al., GCN Circ. 23482).  The BAT ground-calculated position is
RA, Dec = 280.737, 27.976 deg which is
  RA(J2000)  =  18h 42m 56.9s
  Dec(J2000) = +27d 58' 33.4"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a double-peaked structure that starts
at ~T0 and ends at ~T+7 s. The two peaks occur at ~T+1 s and ~T+6 s, respectively.
T90 (15-350 keV) is 6.56 +- 0.61 sec (estimated error including systematics).

The time-averaged spectrum from T-0.26 to T+6.76 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.61 +- 0.24.  The fluence in the 15-150 keV band is 2.5 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.69 sec in the 15-150 keV band
is 0.9 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/874334/BA/


GRB_name: GRB181202A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23490
SUBJECT: GRB 181202A: Global MASTER-Net optical observations 
DATE:    18/12/03 01:24:30 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa,
A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

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

K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory



MASTER-Tunka robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Russia (Applied Physics Institute, Irkutsk State University) was pointed 
to the  Swift GRB 181202A (Cannizzo et al., GCN  #23482) 13216 sec after 
trigger time at 2018-12-02 10:17:08. On best sum (1800s total
exposure)  set 
we haven't found optical transient  within Swift error-box (ra=280.733 
dec=27.9592 r=0.05).

The 5-sigma upper limit has been about 19.0 mag


====================================================================


The galactic latitude b = 14 deg., longitude l = 58 deg.
The observations made on zenit distance = 42 deg.The moon (25 % bright 
part) below the horizon (The altitude of the Moon is -26 deg. ).
  Observations started at twilight.
The sun  altitude  is -10.6 deg.
The object can be observed till sunrise at 2018-12-02 00:56:06

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, 
Kislovodsk Solar Station of Pulkovo observatory) was pointed to the  SWIFT 
GRB181202.28 32902 sec after trigger time at 2018-12-02 15:46:09 UT, with 
upper limit up to  20.2 mag. No OT detected.

The observations began at zenit distance = 57 
deg. The sun  altitude  is -23.0 deg.


This message can be cited.


GRB_name: GRB181201A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23491
SUBJECT: GRB 181201A: Insight-HXMT/HE detection
DATE:    18/12/03 01:41:51 GMT
FROM:    Ce Cai at IHEP  <caice@ihep.ac.cn>

C. Cai, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 
 
At 2018-12-01T02:39:53.000 (T0), the Insight-HXMT/HE detected 
GRB 181201A (trigger ID: HEB181201111) in a routine search of the data, 
which was also triggered by INTEGRAL (S. Mereghetti et al.,GCN 23469);
Fermi/LAT (M. Arimoto et al., GCN23480).
 
The Insight-HXMT/HE light curve mainly consists of Single 
pulse with a duration (T90) of 15.18 s measured from T0+1.56 s. 
The 1-s peak rate, measured from T0+5.28 s, is 13844.5 cnts/s. 
The total counts from this burst is 88444.0 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB181201111_lc.jpg 
 
All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 
 
Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.
 


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23492
SUBJECT: GRB 181201A: Further COATLI Optical Monitoring
DATE:    18/12/03 07:12:44 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William
H. Lee (UNAM), Margarita Pereyra (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM),
Alexander Kutyrev (GSFC), and Eleonora Troja (GSFC), report:

We observed the field of GRB 181201A (Mereghetti et al., GCN 23469) with
the COATLI 50-cm telescope and interim imager at the Observatorio
AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir
(http://coatli.astroscu.unam.mx) from 2018-12-03 01:30:45 to 04:14:39
(from 46.9 to 49.6 hours after the trigger), obtaining a total of 1.5
hours of exposure in the w filter.

We continue to detect the optical counterpart reported by Podesta et al.
(GCN Circ. 23470) at w = 18.77 +/- 0.02.

The counterpart has faded by about 1 magnitude since our previous
observations (Watson et al., GCN 23481). Further observations are
planned.

Our w magnitudes are calibrated against the USNO-B1 catalog (adjusted to
an approximate AB system) and are not corrected for Galactic extinction
in the direction of the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB181203A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23493
SUBJECT: GRB 181203A: Swift detection of a burst
DATE:    18/12/03 12:23:43 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

E. Troja (NASA/GSFC/UMCP), A. P. Beardmore (U Leicester),
A. A. Breeveld (UCL-MSSL), J.D. Gropp (PSU), J. A. Kennea (PSU),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
M. J. Moss (George Washington University), K. L. Page (U Leicester),
D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 12:08:47 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181203A (trigger=874475).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 108.369, -39.769 which is 
   RA(J2000) = 07h 13m 29s
   Dec(J2000) = -39d 46' 07"
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 20 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 12:10:01.1 UT, 73.3 seconds after
the BAT trigger. The position determined from promptly downlinked data
differs significantly from the on-board position, suggesting that the
XRT may have centroided on a cosmic ray; the initial XRT position
notice should be treated with caution. Using promptly downlinked data
we find a fading, uncatalogued X-ray source with an enhanced position:
RA, Dec 108.3491, -39.8016 which is equivalent to:
   RA(J2000)  = 07h 13m 23.78s
   Dec(J2000) = -39d 48' 05.6"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 129 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.26
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 79 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
0.24. 

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: GRB181203A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23494
SUBJECT: GRB 181203A: Enhanced Swift-XRT position
DATE:    18/12/03 14:27:43 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 867 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 181203A, 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 = 108.34857, -39.80187 which is equivalent
to:

RA (J2000): 07h 13m 23.66s
Dec (J2000): -39d 48' 06.7"

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: GRB181201A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23495
SUBJECT: Konus-Wind observation of GRB 181201A
DATE:    18/12/03 16:42:48 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 181201A
(INTEGRAL-IBIS/ISGRI detection: Mereghetti et al., GCN Circ. 23469;
Insight-HXMT/HE detection: Cai et al., GCN Circ. 23491)
triggered Konus-Wind at T0=9592.355 s UT (02:39:52.355).

The burst light curve consists of two well-separated pulses
with the first pulse staring at ~T0-115 s,
and a total burst duration of ~172 s.
The emission is seen up to ~15 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181201_T09592/

As observed by Konus-Wind, the burst
had a fluence of 1.99(-0.06,+0.06)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+4.848 s,
of 2.88(-0.33,+0.34)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+34.816 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.25(-0.05,+0.05),
the high energy photon index beta = -2.73(-0.12,+0.11),
the peak energy Ep = 152(-6,+6) keV
(chi2 = 114/97 dof).

The spectrum near the maximum count rate
(measured from T0+4.352 to T0+4.864 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.75(-0.16,+0.19),
the high energy photon index beta = -2.76(-0.38,+0.21),
the peak energy Ep = 207(-24,+26) keV
(chi2 = 51/49 dof).

Assuming the redshift z=0.450 (Izzo et al., GCN Circ. 23488)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~1.0x10^53 erg,
the peak luminosity L_iso is ~2.2x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is ~220 keV.

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


GRB_name: GRB181202A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23496
SUBJECT: GRB 181202A: RATIR Optical and NIR Observations
DATE:    18/12/03 17:27:42 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:

We observed the field of GRB 181202A (Cannizzo et al., GCN 23482) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)
on the 1.5m Harold Johnson Telescope at the Observatorio AstronÃ³mico
Nacional on Sierra San Pedro MÃ¡rtir from 2018/12 3.09 to 2018/12 3.11
UTC (19.43 to 20.04 hours after the BAT trigger), obtaining a total of
0.09 hours exposure in the r and i bands and 0.12 hours exposure in the
Z, Y, J, and H bands in poor conditions.

For a source within the Swift-XRT error circle, in comparison with the
USNO-B1 and 2MASS catalogs, we obtain the following 3-sigma upper
limits:

 r > 19.18
 i > 19.17
 Z > 16.52
 Y > 16.30
 J > 16.00
 H > 16.31

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

However, we note that in our optimally-combined all-filter image, there
appears to be a very faint source present in the Swift-XRT error circle.
This suggests that there may be a source present at low significance in
at least some of our individual images.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro
MÃ¡rtir.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23497
SUBJECT: GRB 181201A: continued optical observations in SAAO and Chilesope
DATE:    18/12/03 17:38:47 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), E. Mazaeva (IKI), S. Belkin (IKI), D. Buckley (SAAO), 
M. Krugov (AFIF), A. Pozanenko (IKI)  report on behalf of IKI-FuN 
follow-up collaboration:

We continue multicolor observation  the   optical afterglow (e.g. 
Podesta et al., GCN  23470; Kong  GCN 23475)  of INTEGRAL GRB 181201A 
(Mereghetti et al., GCN  23469)  with 1m telescopes of SAAO (SAAO40in) 
and Chilescope (RC1000) observatories.    Preliminary photometry   is 
following

Date       UT start t-T0    Filter Exp.   OT     Err.   Telescope
                     (mid, days)    (s)

2018-12-02 19:09:26 1.69544 r'     2*600  18.69  0.02   SAAO40in
2018-12-02 19:30:07 1.70980 i'     2*600  18.54  0.07   SAAO40in
2018-12-02 19:50:44 1.72759 g'     3*600  19.07  0.05   SAAO40in
2018-12-03 01:32:26 1.95794 r'     600    18.92  0.04   RC1000

The photometry is based on the SDSS DR12 star

SDSS-DR12_id                 g        r        i
J211710.81-123706.3      17.191   16.517   16.257


GRB_name: GRB181202A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23498
SUBJECT: GRB 181202A: Swift/UVOT Detection
DATE:    18/12/04 00:09:57 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and J. K. Cannizzo (NASA/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181202A
86 s after the BAT trigger (Cannizzo et al., GCN Circ. 23482).
A source consistent with the XRT position
(Evans et al. GCN Circ. 23483)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
  RA  (J2000) =  18:42:56.38 = 280.73491 (deg.)
  Dec (J2000) = +27:57:35.0  =  27.95971 (deg.)
with an estimated uncertainty of 0.47 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

v                  623         1540          117        >18.7
b                  342          591          246         19.57 +/- 0.18
u (fc)              86          336          246         17.67 +/- 0.07
w1                 672         1441           97        >19.6
m2                 647         1560          112        >22.2
w2                 598         1516          117        >20.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.14 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181201A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23499
SUBJECT: GRB 181201A: Swift/UVOT Detection
DATE:    18/12/04 00:22:12 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and J. K. Cannizzo (NASA/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 18201A
14.3 ks after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 23469).
We confirm the optical afterglow initially reported by MASTER (Podeta et al.,
GCN Circ. 23470, Kong, GCN Circ. 23475, Volnova et al., GCN Circ. 23477, Mazaeva
et al., GCN Circ. 23479, Watson et al., GCN Circ. 23481, Belkin et al., GCN Circ.
23485, Bolmer and Schady, GCN Circ. 23486, Cai et al., GCN Circ. 23491). The 
position of the afterglow is also consistent with the XRT afterglow
(Page et al., GCN Circ. 23474). The detection of the afterglow in the uvw2
filter would be consistent with the redshift report by Izzy et al. (GCN Circ. 23488).

The preliminary UVOT position is:
  RA  (J2000) =  21:17:11.17 = 319.29656 (deg.)
  Dec (J2000) = -12:37:51.0  = -12.63084 (deg.)
with an estimated uncertainty of 0.2 arc sec. (radius, 90% confidence).

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are:

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

uvw2             14310        26435         4901       15.39 +/- 0.02
white            56416        74104          924       17.53 +/- 0.03
white           148341       165117         1162       18.71 +/- 0.04
v                56713        74204          535       17.70 +/- 0.10
v               160066       165389          389       18.70 +/- 0.26
u                56120        77881         2757       17.25 +/- 0.03
u               148114       164276         2896       18.30 +/- 0.05

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181203A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23500
SUBJECT: GRB 181203A: Swift-BAT refined analysis
DATE:    18/12/04 03:52:49 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
E. Troja (NASA/GSFC/UMCP), T. N. Ukwatta (LANL)
(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 181203A (trigger #874475)
(Troja et al., GCN Circ. 23493).  The BAT ground-calculated position is
RA, Dec = 108.341, -39.783 deg which is
   RA(J2000)  =  07h 13m 21.8s
   Dec(J2000) = -39d 46' 57.1"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.

The mask-weighted light curve shows a single-peaked structure that starts at
~T-2 s, peaks at ~T+1 s, and ends at ~T+16 s. T90 (15-350 keV) is 15.30 +- 1.75 sec
(estimated error including systematics).

The time-averaged spectrum from T-1.96 to T+15.77 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.79 +- 0.15.  The fluence in the 15-150 keV band is 7.8 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+1.02 sec in the 15-150 keV band
is 1.1 +- 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/874475/BA/


GRB_name: GRB181201A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23501
SUBJECT: GRB 181201A: AstroSat CZTI detection
DATE:    18/12/04 05:29:05 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

T. Khanam, V. Sharma and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), D. Bhattacharya (IUCAA), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 181201A, which was also detected by Integral-IBIS/ISGRI detection (Mereghetti S. et al., GCN 23469), Insight-HXMT/HE detection (Cai C. et al., GCN 23491) and Konus-Wind (Svinkin D. et al., GCN 23495).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 02:39:58.020 UT, ~2 min after the Integral-IBAS trigger. The measured peak count rate is 910.8 cts/s above the background in combined data of four quadrants, with a total of 6099 cts. The local mean background count rate was 569 cts/s. Using cumulative rates, we measure a T90 of 19.2 s. In preliminary analysis, we find that 402 compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB181203A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23502
SUBJECT: GRB 181203A: Swift-XRT refined Analysis
DATE:    18/12/04 08:46:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), B.
Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A. Tohuvavohu (PSU),
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester) and E. Troja report on behalf of the Swift-XRT team:

We have analysed 6.2 ks of XRT data for GRB 181203A (Troja et al. GCN
Circ. 23493), from 60 s to 64.1 ks after the  BAT trigger. The data
comprise 9 s in Windowed Timing (WT) mode (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. 23494).

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.74 (+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 1.84 (+0.29, -0.17). The
best-fitting absorption column is  consistent with the Galactic value
of 2.3 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 3.9 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.3 (+/-0.8) x 10^21 cm^-2
Galactic foreground: 2.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.84 (+0.29, -0.17)

If the light curve continues to decay with a power-law decay index of
2.74, the count rate at T+24 hours will be 3.2 x 10^-8 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-18 (1.6 x 10^-18) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00874475.

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


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23503
SUBJECT: GRB181201A: GOTO optical observations
DATE:    18/12/04 14:09:38 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <dsteeghs@gmail.com>

G.Ramsay (Armagh O.), J.Lyman, K.Ulaczyk, D.Steeghs, K.Wiersema
(U. Warwick), M.Dyer (U. Sheffield), B.Gompertz, A.Levan, R.Cutter
(U. Warwick) K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon
(U. Sheffield), P.O'Brien, R.Starling (U. Leicester), S.Poshyachinda
(NARIT), D.Pollacco (U. Warwick), E.Thrane (Monash U.), E.Palle (IAC)

report on behalf of the GOTO collaboration:

The Gravitational-wave Optical Transient Observer observed the field
of the long duration GRB 181201A (Mereghetti et al. GCN Circ. 23469,
Page et al. GCN Circ. 23474) from Roque de los Muchachos Observatory.

We report two optical photometric detections, both made using a
combined L-band image (400-700nm passband), each with a total exposure
time of 300s.  The resulting preliminary magnitudes are based on a
comparison to Panstarrs g-band calibrators and include a systematic
error component due to the calibration uncertainty.

midpoint                 time elapsed since burst   g
2018-12-01 19:33:18 UT   0.705 days                 17.74+/-0.10 mag
2018-12-03 19:41:21 UT   2.711 days                 19.48+/-0.15 mag

GOTO is operated at the La Palma observing facilities of the
University of Warwick on behalf of a consortium including the
University of Warwick, Monash University, Armagh Observatory, the
University of Leicester, the University of Sheffield, the National
Astronomical Research Institute of Thailand (NARIT) and the Instituto
de Astrofisica de Canarias (IAC) (https://goto-observatory.org/)


GRB_name: GRB181201A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23504
SUBJECT: GRB 181201A: Continued GROND observations show that afterglow is still bright
DATE:    18/12/04 15:06:49 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan@bolmer.de>

J. Bolmer (MPE, Garching) and P. Schady (Univ. of Bath) report:

We observed again the field of GRB 181201A (INTEGRAL trigger; Mereghetti et al., GCN #23469)
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted
at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).

Observations started at 01:01 UT on 4. of Dezember 2018, about three days after the
GRB trigger, and were performed under poor seeing conditions, 2.2'', and at an average
airmass of 2.0.

We still detect the afterglow and based on 17 min of total exposure time,
we measure the following preliminary r'-band AB magnitude, indicating
that the afterglow is still reltively bright, even three days after the
detection of the prompt emission:

r' = 19.43 +/- 0.03 mag

Given magnitude is calibrated against SDSS and not corrected for the
expected Galactic foreground extinction corresponding to a reddening of
E_(B-V)=0.05 in the direction of the burst (Schlafly & Finkbeiner 2011).


GRB_name: GRB181203A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23505
SUBJECT: GRB 181203A: Swift/UVOT Upper Limits
DATE:    18/12/04 16:55:56 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181203A
79 s after the BAT trigger (Troja et al., GCN Circ. 23493).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 23494)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposures and subsequent exposures are:

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

white_FC            79          229          147         >20.7
u_FC               293          543          246         >19.4
white               79         1370          373         >21.8
v                  624         1421           97         >18.6
b                  549         1346           78         >20.0
u                  293         1495          324         >19.7
w1                 673         1470           97         >19.0
m2                 648         1445           97         >18.5
w2                 599         1396           97         >19.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.24 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23507
SUBJECT: GRB 181201A: continued optical observations in TSHAO
DATE:    18/12/04 18:59:33 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

I. Reva (AFIF), M. Krugov (AFIF), A. Volnova (IKI), E. Mazaeva (IKI), S. 
Belkin (IKI), A. Pozanenko (IKI)  report on behalf of IKI-FuN follow-up 
collaboration:

We continue observations  the  optical afterglow (e.g. Podesta et al., 
GCN  23470; Kong  GCN 23475)  of INTEGRAL GRB 181201A (Mereghetti et 
al., GCN  23469)   with Zeiss-1000 1-m telescope of Tien Shan 
Astronomical Observatory.  Preliminary photometry  of the afterglow in 
R-filter on December 04 is following

Date       UT start t-T0    Filter Exp.    OT    Err.
                     (mid, days)    (s)

2018-12-04 12:19:26 3.4202   R     2400    19.67 0.07

The photometry is based on the SDSS-DR12 star

SDSS-DR12_id            R(Lupton)
J211710.81-123706.3     16.296


GRB_name: GRB181201A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23510
SUBJECT: GRB181201A: Optical afterglow measurements by GROWTH-India
DATE:    18/12/05 05:07:03 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

Shubham Srivastava (IITB), Harsh Kumar (IITB), Stanzin Otzer (IIA), Kishalay De (Caltech), Varun Bhalerao (IITB), G C Anupama (IIA) and Mansi Kasliwal (Caltech) report on behalf of the GROWTH collaboration:

The long duration GRB181201A (Mereghetti et al., GCN 23469, Sharma et al., 23501) was observed by the GROWTH-India telescope in the g-band for an integration time of 600s. The afterglow was clearly detected, and the magnitude was calibrated using field stars from the PS1 catalog.

t_mid                    delta_t mag     mag_err
2018-12-04 13:27:45 UT   3.4512  19.97   0.13

The GROWTH India telescope is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).

The data were obtained as part of the GROWTH Winter School at IIT Bombay with 70 participants - http://growth.caltech.edu/growth-winter-school-2018.html


GRB_name: GRB180112B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23511
SUBJECT: GRB 180112B: AstroSat CZTI detection
DATE:    18/12/05 05:52:28 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

Y. Sharma and V. Bhalerao (IIT-B), T. Khanam, V. Sharma and A. Vibhute (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of long duration GRB 180112B in the 40-200 keV energy range. The light curve shows weak multiple peak emission starting at 20:12:26 (UT). The measured peak count rate is 283 cts/s above the background in combined data of four quadrants, with a total of 823 cts. The local mean background count rate was 441.4 cts/s. Using cumulative rates, we measure a T90 of 8.48 s.

The GRB was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range with 324.17 cts/s peak count rate above background in combined data of four quadrants.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB181205A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23512
SUBJECT: GRB 181205A: a long GRB detected by INTEGRAL
DATE:    18/12/05 09:42:26 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro.mereghetti@inaf.it>

D.Gotz (CEA, Saclay), S.Mereghetti (INAF, IASF-Milano), C.Ferrigno,
E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC,
Versoix) and J.Borkowski (CAMK, Torun) report:

a gamma ray burst lasting about 60 s has been detected by IBAS in the
IBIS/ISGRI data at 8:41  UT of December 5, 2018.

The refined coordinates (J2000) are:
R.A.= 199.9536 deg
DEC.=   8.1975 deg

with an uncertainty of  1.5   arcmin (90% c.l.).

The burst had a peak flux of 0.8  counts/cm2/s (20-200 keV, 1-s
integration  time) and a fluence in the same energy range of about 2e-6
erg/cmq.

A plot of the light curve will  be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html


GRB_name: GRB181203A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23513
SUBJECT: GRB 181203A: BOOTES-3/YA optical observations
DATE:    18/12/05 11:47:59 GMT
FROM:    Youdong HU at IAA-CSIC, UGR  <youdong@iaa.es>

Y.-D. Hu, E. Fernandez-Garcia, A. Ayala and A. J. Castro-Tirado 
(IAA-CSIC), I. Carrasco and C. Perez del Pulgar (Univ. de Malaga), M. D. 
Caballero-Garcia (ASU-CAS, CZ) and R. Querel (NIWA), on behalf of a 
larger collaboration,
report:

The 60cm BOOTES-3/YA robotic telescope at NIWA Lauder in Otago (New 
Zealand) automatically responded to the Swift trigger of GRB 181203A 
(Troja et al. GCNC 23493) ~0.51 h after the burst.  At the position of 
the Swift/XRT enhanced X-ray position (Goad et al. GCNC 23494), no 
optical afterglow is detected down to 20.4 mag on a 360s co-added 
unfiltered image at 0.62 h (middle exposure) after trigger, in agreement 
with the non-detection by Swift/UVOT (Marshall et al. GCNC 23505).

We thank the staff at NIWA for its excellent support.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23514
SUBJECT: GRB 181201A: continued optical observations in TSHAO and Chilesope
DATE:    18/12/05 20:49:30 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI),  I. Reva (FAI), A. Pozanenko (IKI), A. Volnova (IKI), 
E. Mazaeva (IKI), A. Kusakin (FAI), M. Krugov (FAI),  D. Buckley (SAAO) 
report on behalf of IKI-FuN follow-up collaboration:

We continue multicolor observations  the   optical afterglow (e.g. 
Podesta et al., GCN  23470; Kong  GCN 23475)  of INTEGRAL GRB 181201A 
(Mereghetti et al., GCN  23469)  with 1m telescopes of TSHAO 
(Zeiss-1000) and Chilescope (RC1000) observatories.    Preliminary 
photometry   is following

Date       UT start t-T0    Filter Exp.   OT     Err.   Telescope
                     (mid, days)    (s)

2018-12-05 01:04:38 3.92822 r'     1200   19.74  0.05   RC-1000
2018-12-05 12:17:22 4.42306 R      2280   19.82  0.07   Zeiss-1000/TSHAO

The photometry is based on the SDSS-DR12 star

SDSS-DR12_id                 g        r        i      R(Lupton)
J211710.81-123706.3         17.191   16.517   16.257  16.296


GRB_name: GRB181126B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23515
SUBJECT: GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175)
DATE:    18/12/07 05:14:50 GMT
FROM:    Tomas Ahumada at U. of Maryland  <tahumada@astro.umd.edu>

Authors: Tomas Ahumada (UMD), Michael W. Coughlin (Caltech), S. Bradley
Cenko (NASA GSFC), Leo P. Singer (NASA GSFC), Shaon Ghosh (UWM), Igor
Andreoni (Caltech), Mansi M. Kasliwal (Caltech), Eric C. Bellm (UW), V.
Zach Golkhou (UW), Ryosuke Itoh (Tokyo Tech), Anna Ho (Caltech), Yuhan Yao
(Caltech), Jacob Jencson (Caltech), Matt Hankins (Caltech), Kishalay De
(Caltech), Virginia Cunningham (UMD) on behalf of the ZTF and GROWTH
collaborations and the KPED team

We observed the localization region of the short GRB181126B (trigger
564897175) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi
satellite with the Palomar 48-inch telescope equipped with the 47 square
degree Zwicky Transient Facility (ZTF) camera. We obtained two sets of 180
second r-band images covering 1400 square degrees beginning at 5:15 UT on
2018 November 26 (1 hour and 23 minutes after the burst trigger time).
Accounting for area lost to processing failures, this corresponds to
analyzing 66% of the probability enclosed. Beginning at 6:06 UT on 2018
November 27 we observed the updated IPN localization with ZTF using 300
second r-band exposures. The observations covered 709 square degrees. Once
again accounting for processing failures, 77% of the enclosed probability
was analyzed.

The images were processed through the ZTF reduction and image subtraction
pipelines at IPAC to search for potential counterparts. 394
high-significance transient and variable candidates were identified by our
pipeline in the area observed,  most (383) of which had previous detections
with ZTF in the days and weeks prior to the GRB trigger time (e.g.,
supernovae, active galactic nuclei, CV).

Further follow-up of 11 transients was obtained with the Kitt Peak EMCCD
Demonstrator (KPED) on the Kitt Peak 84-inch telescope on November 28.
Additionally, we obtained follow-up spectroscopy of 6 candidates with the
Low Resolution Imaging Spectrometer (LRIS) on Keck I, the nights of
December 1 and December 3. The candidates are listed below, however no
photometric evolution or spectral classification was consistent with an
optical counterpart.

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

       ZTF ID         RA DEC      last non-detection discovery    KPED
Classification

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


                             deg deg date in 2018          Nov 26 Nov 28

----------------------------------------------------------------------------------------------------------------------------
ZTF18achtkfy     103.5113 37.0748    11-09 g<19.94 r = 19.69   r = 20.95
SN* (Rising)
ZTF18acpftxl     102.7187 29.3472     11-21 r<20.43 r = 20.11   r > 20.93
Asteroid* (1 det)
ZTF18achflqs      70.2895 23.8902   11-10 r<20.37 r = 20.74   r = 20.26 SN*
(Rising)
ZTF18acrkcxa     73.7605 22.6787   11-21 r<19.68 r = 21.21    r = 20.87 SN*
(Rising)
ZTF18acrkkpc     95.8148 10.323    11-21 r<20.17 r = 20.17    r = 19.85 SN*
(Rising)
ZTF18aadwfrc     94.3249 50.4844   11-25 r<19.33 r = 18.96    r = 18.13 SN
II z=0.04
ZTF18acrfond     59.8623 24.589     11-25 r<19.38 r = 19.93    r = 18.87 SN
Ia z=0.117
ZTF18acrfymv     94.5049 44.1813   11-25 r<19.13 r = 20.05    r = 19.60 S
NIc-BL
<http://skipper.caltech.edu:8080/cgi-bin/growth/edit_comment.cgi?name=ZTF18acrfymv&id=11173>
z=0.
<http://skipper.caltech.edu:8080/cgi-bin/growth/edit_comment.cgi?name=ZTF18acrfymv&id=11174>
072
ZTF18acptgzz     68.3852 -1.6475    11-25 r<19.22 r = 19.01   r = 19.04 SN
Ia z=0.096

ZTF18acbyrll       88.8695 29.4723 11-21   r<19.84 r = 18.79 r > 21.87
  Asteroid* (1 det)

ZTF18acrewzd    70.3221 -1.7688     11-25 r<19.17 r = 20.21   r = 19.9 SN
Ia z=0.13

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

*Classification from photometric data points.

The median 5-sigma upper limit for an isolated point source in ZTF images
was r > 20.5 mag for the observations made on November 26 and r > 21.1 mag
for the observations made on November 27.

ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266
<http://www.astronomerstelegram.org/?read=11266>), and includes IPAC; WIS,
Israel; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; MOST, Taiwan; UW
Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the
NSF under AST MSIP Grant No 1440341. Alert distribution service provided by
DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system,
supported by NSF PIRE grant 1545949.


GRB_name: GRB181203A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23516
SUBJECT: GRB 181203A: GROND detection of the afterglow
DATE:    18/12/07 06:57:50 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan@bolmer.de>

P. Schady (Univ. of Bath) and J. Bolmer (MPE, Garching) report:

We observed the field of GRB 181203A (Swift trigger 874475; Troja et al., GCN #23493) simultaneously in
g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO
La Silla Observatory (Chile).

Observations started at 02:02 UT on 4th December, 13.4 hours after the GRB trigger. They were performed
at an average seeing of 1.6" and at an average airmass of 1.4. 

We found a faint source within the 2.0 arcsec Swift-XRT error circle reported by Goad et al. (GCN #23494) at

RA (J2000) = 07:13:23.705
DEC (J2000) = -39:48:05.29

with an uncertainty of 0.12" in each coordinate. The source is detected in all filters apart from the z' band,
and has a preliminary r'-band AB magnitude of 

r' = 23.5 +/- 0.1 mag

The above magnitude is calibrated against GROND zeropoints and is not corrected for the expected
Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.21 in the direction of the
burst (Schlafly & Finkbeiner 2011).

We thank Angela Hempel for the excellent support from La Silla. 


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23518
SUBJECT: GRB 181201A: ALMA detection of a fading mm afterglow
DATE:    18/12/07 17:08:24 GMT
FROM:    Tanmoy Laskar at UC Berkeley  <tanmoylaskar@gmail.com>

T. Laskar (University of Bath), E. Berger (Harvard), R. Chornock (Ohio
University), W. Fong (Northwestern), R. Margutti (Northwestern), C. G.
Mundell (University of Bath), and P. Schady (University of Bath) report on
behalf of a larger collaboration:

"We observed GRB 181201A (Mereghetti et al. GCN 23469) with the Atacama
Large Millimeter/Submillimeter Array (ALMA) starting at 0.9 d after the
burst at 90 GHz. Preliminary analysis reveals a bright (S/N > 150), fading
mm counterpart at a location consistent with the X-ray position (Page et
al. GCN 23474) and optical position (Podesta et al., GCN 23470; Lipunov et
al., GCN 23476, GCN 23484; Siegel & Cannizzo, GCN 23499). Follow-up
observations are planned.

We thank the JAO staff, AoD, and the ALMA team for their help with these
observations."


GRB_name: GRB181201A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23519
SUBJECT: GRB 181201A: VLA detection
DATE:    18/12/07 18:52:33 GMT
FROM:    Tanmoy Laskar at UC Berkeley  <tanmoylaskar@gmail.com>

T. Laskar (University of Bath), E. Berger (Harvard), R. Chornock (Ohio
University), W. Fong (Northwestern), R. Margutti (Northwestern), C. G.
Mundell (University of Bath), and P. Schady (University of Bath) report on
behalf of a larger collaboration:

"We observed GRB 181201A (Mereghetti et al. GCN 23469) with the Karl G.
Jansky Very Large Array (VLA) beginning on 2018 December 04.02 UT (2.9 d
after the burst). At a mean frequency of 6.0 GHz, we detect a radio source
at the position

RA (J2000) = 21:17:11.185 +/- 0.001
Dec (J2000) = -12:37:51.37 +/- 0.03

consistent with the position of the optical afterglow (Podesta et al., GCN
23470; Lipunov et al., GCN 23476, GCN 23484; Siegel & Cannizzo, GCN 23499)
and the XRT afterglow (Page et al. GCN 23474). Follow-up observations are
planned.

We thank the VLA staff for rapidly executing these observations."


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23522
SUBJECT: GRB 181201A: continued optical observations in Mondy
DATE:    18/12/09 20:12:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI),  E. Klunko (ISTP),  S. Belkin (IKI), A. Volnova (IKI), 
  A. Pozanenko (IKI) report on behalf of of larger GRB follow-up 
collaboration:

We continue  observations  the   optical afterglow (e.g. Podesta et al., 
GCN  23470; Kong  GCN 23475)  of INTEGRAL GRB 181201A  (Mereghetti et 
al., GCN  23469)  with   AZT-33IK telescope of Sayan observatory 
(Mondy).    Preliminary photometry of the OT is following.

Date        UT start  t-T0  Filter Exp.   OT     Err.
                       (mid, days)  (s)

2018-12-03 11:24:39 2.38658 R      30*120 18.91  0.03
2018-12-05 11:26:24 4.38780 R      30*120 20.03  0.09
2018-12-07 10:57:13 6.36753 R      30*120 20.23  0.05


The photometry is based on the SDSS-DR12 star

SDSS-DR12_id           R(Lupton)
J211710.81-123706.3    16.3


GRB_name: GRB181126B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23523
SUBJECT: GRB 181126B: KAIT Follow-Up Observations of a Fermi Short GRB (Trigger 564897175)
DATE:    18/12/12 19:45:56 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng, Keto Zhang, Alexei V. Filippenko, and Sergiy Vasylyev
(UC Berkeley) report on behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, observed the field of the short GRB181126B (trigger
564897175) detected by the GBM on the Fermi satellite.
More than one thousand galaxies were selected from the
Glade catalog (http://aquarius.elte.hu/glade/) according to
their priority score. On 2018 Nov. 26 UT, KAIT observed 236 of them having
top-priority scores, with each clear-filter exposure time being 60 s.
The first image was taken at 07:41:13 UT,  about 3.8 hr after the burst, and
the last image at 11:51:09 UT. Template images were obtained on 2018
Dec. 8 and 9. The images were processed through the KAIT
subtraction pipeline to search for potential optical counterparts.
13 known asteroids were detected, but we found no credible transient
that might be the optical afterglow of this GRB.  None of the 11
transients reported by Ahumada et al. (GCN 23515) was in the field of
view of the KAIT images. Our typical limiting mag is 19.0, although some
fields have a shallower limiting mag owing to moonlight.


GRB_name: GRB181212A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23524
SUBJECT: GRB 181212A: Fermi GBM Detection
DATE:    18/12/13 02:19:16 GMT
FROM:    C. Michelle Hui at MSFC/Fermi-GBM  <c.m.hui@nasa.gov>

C. L. Fletcher (USRA)

report on behalf of the Fermi GBM Team:



"At 16:37:46.05 UT on 12 December 2018, the Fermi Gamma-Ray Burst Monitor

triggered and located GRB 181212A (trigger 566325471 / 181212693).



The on-ground calculated location, using the GBM trigger

data, is RA = 298.4, DEC = -3.7 (J2000 degrees,

equivalent to 19 h 53 m 33.60 s, -03 d 42 '), with an uncertainty

of 2.3 degrees (radius, 1-sigma containment,

statistical only; there is additionally a systematic

error which we have characterized as a core-plus-tail model, with 90% of

GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg

systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).



The angle from the Fermi LAT boresight at the GBM trigger time is 114 degrees.



The GBM light curve consists of a bright pulse

with a duration (T90) of about 58 s (50-300 keV).

The time-averaged spectrum from T0+0 s to T0+58 s is

best fit by a Band function with Epeak = 72 +/- 8 keV,

alpha = -1.4 +/- 0.1, and beta = -2.2 +/- 0.1



The event fluence (10-1000 keV) in this time interval is

(2.138 +/- 0.052)E-05 erg/cm^2. The 1-sec peak photon flux measured

starting from T0+1.9 s in the 10-1000 keV band

is 66 +/- 1 ph/s/cm^2.



The spectral analysis results presented above are preliminary;

final results will be published in the GBM GRB Catalog."


GRB_name: GRB181213A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23525
SUBJECT: GRB 181213A: Swift detection of a burst
DATE:    18/12/13 13:08:00 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

P. A. Evans (U Leicester), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),
K. L. Page (U Leicester) and A. Tohuvavohu (PSU) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 12:57:38 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181213A (trigger=876016).  Swift will slew at ~T+33 min
due to an observing constraint.  The BAT on-board calculated location is 
RA, Dec 248.207, +78.504, which is 
   RA(J2000)  =  16h 32m 50s
   Dec(J2000) = +78d 30' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows multiple peaks
with a total duration of about 25 sec.  The peak count rate
was ~850 counts/sec (15-350 keV), at ~1 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+33.8
minutes. There will be no XRT or UVOT data until this time. 

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


GRB_name: GRB181213A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23526
SUBJECT: SWIFT GRB181213A Global MASTER-Net bright OT discovery
DATE:    18/12/13 14:00:20 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, 
P.Balanutsa,
A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

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

K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory



MASTER-Amur robotic telescope  (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical 
University) was pointed to the  SWIFT GRB181213.54 (Evens et al. GCN 
23525) 81 sec after trigger time at 2018-12-13 12:58:59 UT, 
with upper limit up to  17.3 mag. The observations began at zenit distance 
= 51 deg. The sun  altitude  is -50.9 deg.

We find bright OT  at a position
  16h 33m 04.88s , +78d 29m 48.15s
with magnitude is about 14.9


The galactic latitude b = -60 deg., longitude l = 98 deg.


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23527
SUBJECT: GRB 181213A: BOOTES-5/JGT optical observations
DATE:    18/12/13 14:02:26 GMT
FROM:    Youdong HU at IAA-CSIC, UGR  <youdong@iaa.es>

Y.-D. Hu, I. Carrasco, E. Fernandez-Garcia and A. J. Castro-Tirado 
(IAA-CSIC),
D. Hiriart and W. H. Lee (UNAM), S. Jeong and I. H. Park (SKKU) and M. 
D.
Caballero-Garcia (ASU-CAS, CZ) on behalf of a larger collaboration, 
report:

The 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico
Nacional in San Pedro Martir (Mexico) automatically responded in 95 s
to the Swift trigger of GRB 181213A Evans et al., GCNC 23525).
The first image (10s exposure, g-band) was obtained at 12:59:13.72 UT.
Within the Swift/BAT error box, we identify an optical source at 
coordinates
RA = 16 33 04.75 Dec = +78 29 48.3 (J2000) of about 15.6 mag, which is 
fading
in brightness in the late time images. Therefore we propose this source 
to be
the optical afterglow to GRB 181213A. Spectroscopic bbservations are 
encouraged.

We thank the staff at Observatorio Astronomico Nacional in San Pedro
Martir for its excellent support.


GRB_name: GRB181213A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23528
SUBJECT: GRB 181213A: Swift-XRT observations
DATE:    18/12/13 14:07:01 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.P. Osborne (U. Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU), G.
Tagliaferri (INAF-OAB), S. Campana (INAF-OAB) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 181213A at 13:36:41.2 UT,
2342.8 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 248.27284,
78.49726 which is equivalent to:
   RA(J2000)  = 16h 33m 05.48s
   Dec(J2000) = +78d 29' 50.1"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 53 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 4.49
x 10^20 cm^-2 (Willingale et al. 2013). 


GRB_name: GRB181213A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23529
SUBJECT: GRB181213A: Swift/UVOT Detection
DATE:    18/12/13 14:28:38 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and P. A. Evans (U Leicester) report on behalf of the Swift UVOT team:
 
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 2352 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
 RA(J2000)  = 16:33:04.87 = 248.27028
 DEC(J2000) = +78:29:48.8  =  78.49690
with a 90%-confidence error radius of about 0.75 arc sec. This position is 2.2
arc sec. from the center of the XRT error circle and consistent with the optical
afterglow reported by MASTER (Lipunov et al., GCN Circ. 23526) and BOOTES
(Hu et al., GCN Circ. 23527). The estimated magnitude is
17.26 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.04. 

[GCN OPS NOTE(13dec18):  The "A" was added tot he GRB designation in the SUBUJECT-line.]


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23530
SUBJECT: GRB 181213A : TSHAO optical observations
DATE:    18/12/13 17:45:03 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Kusakin (FAPHI), A. Pozanenko (IKI), I. Reva 
(FAPHI), A. Volnova (IKI),  E. Mazaeva (IKI), M. Krugov (FAPHI) report 
on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne 
et al., GCN 23528) with Zeiss-1000 1-m telescope of Tien Shan 
Astronomical Observatory starting on Dec. 13 (UT) 13:39:23.  We detected 
the OT reported earlier (Lipunov et al., GCN 23526; Hu et al. GCN 23527; 
  Siegel  et al., GCN 23529). Preliminary photometry of the object is 
following.

Date       UT start t-T0    Filter Exp. OT    Err. UL
                     (mid, days) (s)

2018-12-13 13:39:23 0.04427 R      2640 17.27 0.08 21.8

The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1684-0061916 15.83
1684-0061968 16.55


GRB_name: GRB181126A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23531
SUBJECT: GRB 181126A: MeerKAT radio observation
DATE:    18/12/13 22:19:16 GMT
FROM:    Alexander van der Horst at George Washington U  <ajvanderhorst@gwu.edu>

L. Rhodes, D. Williams (Oxford), R.P. Fender (Oxford/UCT), A.J. van der
Horst (GWU), A. Horesh (HUJI), K. Mooley (NRAO/Caltech) and P.A. Woudt
(UCT) report on behalf of the ThunderKAT collaboration:

â€œWe observed the position of the GRB 181126A afterglow at 1.3 GHz with
the new MeerKAT radio telescope on November 28, from 3.55 to 4.72 UT,
i.e. 1.76 days after the burst (GCN 23453). We do not detect a radio source
at the position of the X-ray counterpart (GCN 23455). The rms noise in the
map around that position is 30 microJy per beam.

These observations were taken as part of the ThunderKAT Large Survey
Project, a 5-year program for observations of transients with MeerKAT.
We would like to thank the staff at the South African Radio Astronomy
Observatory (SARAO) for scheduling and obtaining these observations.â€


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23532
SUBJECT: GRB 181213A: GWAC-F60A upper limit 
DATE:    18/12/14 01:48:15 GMT
FROM:    L.P. Xin at NAOC  <xlp@nao.cas.cn>

X. H. Han, R. S. Zhang,  L. P. Xin,  J. Wang,  P. P. Zhang, J. Y. Wei,   E. W. Liang, 
X. G. Wang, Y. J. Xiao,   Y. G. Yang,  X. M. Lu,  L. Huang,    H. B. Cai,   
X. M. Meng,   Y. L. Qiu,  Y. Xu, Y.  J. Xiao, Y. T. Zheng,  C. Wu,   
J. S. Deng, D. W. Xu,  D. TURPIN, H. L. Li, and W. L. Dong, report:

We  observed  GRB 181213A  ( Evans et al., GCN 23525; Osborne 
et al., GCN 23528 )  with  GWAC-F60A 60cm optical telescope 
at 21:21:34 UT, Dec. 13th 2018,  about 8.4  hours after the burst. 
The exposure time is 150 sec in R band. the airmass is 1.56. 

The optical afterglow reported by (Lipunov et al., GCN 23526; Hu et al. GCN 23527; 
 Siegel  et al., GCN 23529; Belkin et al., GCN 23530) is not detected with an upper 
limit of 18.2 mag in R band image. The brightness is calibrated by nearby USNO-B1.0 stars.

GWAC-F60A is operated by Guangxi university and NAOC, CAS, 
at Xinglong observatory, China.

The message may be cited.


GRB_name: GRB181213A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23533
SUBJECT: GRB 181213A: Swift-BAT refined analysis
DATE:    18/12/14 05:04:44 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 181213A (trigger #876016)
(Evans et al., GCN Circ. 23525).  The BAT ground-calculated position is
RA, Dec = 248.210, 78.500 deg which is
  RA(J2000)  =  16h 32m 50.5s
  Dec(J2000) = +78d 30' 00.7"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 21%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T-1 s and ends at ~T+16 s. Note that the burst went out of the BAT
field of view at ~T+100 s. T90 (15-350 keV) is 15.31 +- 1.24 sec (estimated
error including systematics).

The time-averaged spectrum from T-0.70 to T+15.94 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.57 +- 0.20.  The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+1.16 sec in the 15-150 keV band
is 2.1 +- 0.6 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/876016/BA/


GRB_name: GRB181212A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23534
SUBJECT: IPN Triangulation of GRB 181212A (long)
DATE:    18/12/14 07:42:53 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

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

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

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

and

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

The long-duration GRB 181212A
(Fermi-GBM detection: Fletcher, GCN Circ. 23524)
was detected by Fermi (GBM trigger 566325471), Konus-Wind,
INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and Swift (BAT)
at about 59866 s UT (16:37:46).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   300.663 (20h 02m 39s)  -0.324 ( +0d 19' 27")
  Corners:
   301.111 (20h 04m 27s)  +1.224 ( +1d 13' 26")
   300.707 (20h 02m 50s)  +1.563 ( +1d 33' 47")
   300.075 (20h 00m 18s)  -3.456 ( -3d 27' 22")
   300.497 (20h 01m 59s)  -3.868 ( -3d 52' 05")
  ---------------------------------------------
The error box area is about 2.31 sq. deg, and its maximum
dimension is 5.43 deg (the minimum one is 29 arcmin).
The Sun distance was about 43 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB181212_T59862/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB181213A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23535
SUBJECT: GRB 181213A: Enhanced Swift-XRT position
DATE:    18/12/14 09:44:59 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 760 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 181213A, 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 = 248.27007, +78.49697 which is equivalent
to:

RA (J2000): 16h 33m 4.82s
Dec (J2000): +78d 29' 49.1"

with an uncertainty of 1.6 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: GRB181213A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23536
SUBJECT: GRB 181213A: Swift-XRT refined Analysis
DATE:    18/12/14 10:00:33 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), A.
Tohuvavohu (PSU), S. J. LaPorte (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai
(INAF-IASFPA) and P.A. Evans report on behalf of the Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 181213A (Evans et al. GCN
Circ. 23525), from 2.4 ks to 37.9 ks after the BAT trigger. The data
comprise 218 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. 23535).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.44 (+0.10, -0.09).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.06 (+0.22, -0.20). The
best-fitting absorption column is  7.2 (+5.4, -2.8) x 10^20 cm^-2,
consistent with the Galactic value of 4.5 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.2 x 10^-11 (3.8 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      7.2 (+5.4, -2.8) x 10^20 cm^-2
Galactic foreground: 4.5 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.06 (+0.22, -0.20)

If the light curve continues to decay with a power-law decay index of
1.44, the count rate at T+24 hours will be 2.2 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.9 x
10^-14 (8.3 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/00876016.

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


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23537
SUBJECT: GRB 181213A: NOT optical observations
DATE:    18/12/14 10:01:41 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI  <keh14@hi.is>

K. E. Heintz (Univ. of Iceland), D. B. Malesani (DAWN/NBI/DTU and DARK/NBI), J. P. U. Fynbo (DAWN/NBI/DTU), A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), L. Balaguer-NuÃ±ez, J. Carbajo (Dept. FQA, Univ. de Barcelona), F. Galindo and C. Perez (NOT), report on behalf of a larger collaboration:

We observed the optical afterglow (Lipunov et al., GCN 23526; Hu et al., GCN 23527; Siegel et al., GCN 23529; Belkin et al., GCN 23530) of GRB 181213A (Evans et al., GCN 23525) with the 2.5-m Nordic Optical Telescope (NOT) equipped with AlFOSC.

Spectroscopy was secured: we obtained 4x900s exposures using grism 4 (with a wavelength coverage from 350 to 900 nm) starting at 23:27:14 UT on December 13 (i.e. 10.5 hr after trigger). The observations were obtained at a seeing around 1â€ but at an airmass > 3. From the acquisition image taken without filter we measure r = 20.6 +/- 0.2 AB mag, calibrated against SDSS r-band Pan-STARRS local photometry. The combined spectrum shows a low-S/N, mostly featureless continuum. Based on the detected continuum down to 415 nm we infer an upper limit on the redshift for the GRB of z < 2.4.


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23538
SUBJECT: GRB 181213A: HMM-0.5m, NEXT-0.6m, CNEOST-1m optical observations
DATE:    18/12/14 11:07:54 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

Z.P. Zhu, D. Xu (NAOC), X. Zhang, J.H. Liu (XAO), B. Li, H.B. Zhao 
(PMO), X. Gao (Urumqi No.1 Senior High School), M. Yang (XJTS) report:

We observed the field of GRB 181213A (Evans et al., GCN 23525; Lipunov 
et al., GCN 23526; Hu et al., GCN 23527) using the HMT-0.5m telescope 
located at Gao-Ya-Zi, Xinjiang, China at 14:32:10 on 2018-12-13, i.e., 
1.57hr after the Swift trigger, and obtained 45x90s, 1x120s, 1x180s 
unfiltered frames.

The afterglow is clearly detected in part of the HMT images, and 
preliminary results are as follows:

Date             Tstart (UT) T-T0(hr) Exp.(s)    Mag(R)
2018-12-13     14:55:00 1.95         3x90         18.0+/-0.1
2018-12-13     15:00:25 2.03         5x90         18.1+/-0.1

We also used the NEXT-0.6m telescope located at Nanshan, Xinjiang, at 
14:49:04 UT on 2018-12-13, i.e., 1.85hr after the Swift trigger and 
obtained 5x90s R-band frames under  cloudy weather. The afterglow is not 
detected down to a limiting magnitude of R~17 mag, calibrated with the 
SDSS field.

Additionally, the CNEOST-1m telescope started observation at 21:43:36 on 
2018-12-13, i.e., 8.76hr after the Swift trigger and we obtained 15x90s 
VR-band frames. The afterglow is not detected down to a 3-sigma upper 
limit of ~20.3 mag.


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23539
SUBJECT: GRB 181213A: AbAO optical observations
DATE:    18/12/14 11:31:27 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), 
V.R. Ayvazian (AbAO),    G. V.  Kapanadze (AbAO),   E. Mazaeva (IKI), 
A. Volnova  (IKI),  I. Molotov (KIAM) report on behalf of larger GRB 
follow-up collaboration:

We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne 
et al., GCN 23528) with AS-32 (0.7m) telescope of Abastumani Observatory 
starting on Dec. 13 (UT) 15:42:55.  We detected the OT   (e.g. Lipunov 
et al., GCN 23526; Hu et al. GCN 23527;  Siegel  et al., GCN 23529; 
Belkin et al., GCN 23530). Preliminary photometry of the afterglow is 
following.

Date       UT start t-T0   Filter Exp.  OT    Err. UL
                     (mid, days) (s)

2018-12-13 15:42:55 0.13264 R     65*60 18.75 0.08 20.9

The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1684-0061916 15.83
1684-0061968 16.55


GRB_name: GRB181212A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23540
SUBJECT: Konus-Wind observation of GRB 181212A
DATE:    18/12/14 11:40:05 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long GRB 181212A (IPN Triangulation: Hurley et al., GCN 23534;
Fermi-GBM detection: Fletcher, GCN 23524)
triggered Konus-Wind at T0=59862.922 s UT (16:37:42.922).

The burst light curve shows a single bright pulse followed
by a weaker extended emission.
The total duration of the burst (T90, 80-1300 keV) is ~66 s.
The emission in the main peak is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(2.4 Â± 0.5)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+1.536 s, of (1.02 Â± 0.13)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+72.448 s)
is best fit in the 20 keV - 15 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -1.75(-0.08,+0.08),
and the peak energy Ep = 216(-45,+84) keV,
chi2 = 100/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and only an upper limit on beta (<-2.3).

The spectrum near the peak count rate (measured from T0
to T0+6.912 s) is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.55 (-0.12,+0.09),
the high energy photon index beta = -2.38 (-7.62,+0.14),
the peak energy Ep = 158 (-20,+47) keV,
chi2 = 101/95 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181212_T59862/

All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.


GRB_name: GRB181212A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23541
SUBJECT: GRB 181212A:Insight-HXMT/HE detection
DATE:    18/12/15 11:34:45 GMT
FROM:    Shuo Xiao at IHEP  <xiaoshuo@ihep.ac.cn>

S. Xiao, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 
At 2018-12-12T16:37:45.500 (T0), the Insight-HXMT/HE detected 
GRB 181212A (trigger ID: HEB181212692) in a routine search of the data, 
which was also triggered by Fermi/GBM (Fletcher et al., GCN23524) and
Konus-Wind (Frederiks et al., GCN23540).
The Insight-HXMT/HE light curve mainly consists of single 
pulse with a duration (T90) of 5.48 s measured from T0+0.72 s. 
The 1-s peak rate, measured from T0+2.07 s, is 8019.2 cnts/s. 
The total counts from this burst is 20371.7 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB181212692_lc.jpg 
All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 
Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB181213A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23542
SUBJECT: GRB 181213A:Insight-HXMT/HE detection
DATE:    18/12/15 11:37:34 GMT
FROM:    Shuo Xiao at IHEP  <xiaoshuo@ihep.ac.cn>

S. Xiao, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2018-12-13T12:57:38.000 (T0), the Insight-HXMT/HE detected 
GRB 181213A (trigger ID: HEB181213540) in a routine search of the data, 
which was also triggered by Swift/BAT (Evans et al., GCN23525).

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 15.67 s measured from T0+0.74 s. 
The 1-s peak rate, measured from T0+1.81 s, is 738.8 cnts/s. 
The total counts from this burst is 6164.7 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB181213540_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23543
SUBJECT: GRB 181213A: continued TSHAO optical observations
DATE:    18/12/16 11:01:22 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Kusakin (FAPHI), A. Pozanenko (IKI), I. Reva 
(FAPHI), E. Mazaeva (IKI), A. Volnova (IKI),  M. Krugov (FAPHI) report 
on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne 
et al., GCN 23528) with Zeiss-1000 1-m telescope of Tien Shan 
Astronomical Observatory starting on Dec. 14 (UT) 13:29:58.  We detected 
the afterglow (Lipunov et al., GCN 23526; Hu et al. GCN 23527;  Siegel 
et al., GCN 23529; Belkin et al., GCN 23530; Heintz et al., GCN 23537). 
Preliminary photometry of the object is following.

Date       UT start t-T0    Filter Exp. OT    Err. UL
                     (mid, days) (s)

2018-12-14 13:29:58 1.06482 R      7200 21.65 0.28 21.9

The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1684-0061916 15.83
1684-0061968 16.55


GRB_name: GRB181213A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23544
SUBJECT: GRB 181213A: Mondy optical observations
DATE:    18/12/16 22:42:44 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), E. Mazaeva (IKI), A. 
Volnova (IKI)  report   on behalf of IKI-FuN:

 We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne   et 
al., GCN 23528) with AZT-33IK telescope of Sayan observatory (Mondy).   We 
marginally detected   the afterglow (Lipunov et al., GCN 23526; Hu et al. 
GCN 23527;  Siegel   et al., GCN 23529; Belkin et al., GCN 23530; Heintz et 
al., GCN 23537) on Dec. 15 (UT start) 11:57:21

  Preliminary photometry of the filed and and the aferglow is following.

  Date       UT start t-T0    Filter Exp. OT    Err. UL
                    (mid, days) (s)

 2018-12-14 12:10:22 0.97344 R      10*120 n/d  n/d   20.9
 2018-12-15 11:57:21 1.97829 R      29*120 23.15 0.45  23.1


 The photometry is based on nearby USNO-B1.0 stars
 USNO-B1.0_id R2
 1684-0061916 15.83
 1684-0061968 16.55
 


GRB_name: GRB181213A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23545
SUBJECT: GRB 181213A: Swift/UVOT Observations 
DATE:    18/12/18 20:20:49 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181213A
2352 s after the BAT trigger (Evans et al., GCN Circ. 23525).  A fading
optical afterglow consistent with initial reports (Lipunov et al., GCN
Circ. 23526, Hu et al., GCN Circ. 23529) was detected in four of UVOTâ€™s
filters. The lack of detection of this bright burst in the bluer filters
would imply a redshift of z > 1.4, which is not inconsistent with the
spectroscopic redshift of z < 2.4 from Heintz et al. (GCN Circ. 23537).

The preliminary UVOT position is:
  RA  (J2000) =  16:33:04.86 = 248.27025 (deg.)
  Dec (J2000) = +78:29:48.7  =  78.49685 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

white (fc)        2353         2503          294      17.33+/-0.04
white             2633         2653           19      17.15+/-0.10
white             8535         9061          513      19.03+/-0.07
white            66263        67021          738            >21.71
v                 2683         2703           19            >17.35
v                26217        37929         1168            >20.45
b                 2608         3393           87      17.82+/-0.10
b                 8330        15947          230      19.18+/-0.23
b                65351        82801         1115            >20.39
u                 2584         3318          216      17.25+/-0.06
u                14999        33141         1327      19.69+/-0.10
u                71983        72421          426            >20.32
uvw1              2559         3113          216      17.50+/-0.11
uvw1             14093        32991         2656      20.07+/-0.16
uvw1             71077        71977          885            >19.97
uvm2              2708         2908          196            >19.26
uvm2             19555        32084         2047            >20.84
uvw2              2659         2679           19            >17.50
uvw2             25310        37634         1771            >20.67

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB181217A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23546
SUBJECT: GRB 181217A: Insight-HXMT/HE detection
DATE:    18/12/19 11:10:35 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2018-12-17T15:56:57.00 (T0), the Insight-HXMT/HE detected
GRB 181217A(trigger ID: HEB181217664) in a routine search of the data,
which was also triggered by Fermi/GBM (trigger_num:566755024).

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 25.59 s measured from T0-0.28 s.
The 1-s peak rate, measured from T0+2.7660 s, is 498.6 cnts/sec.
The total counts from this burst is 6118.1 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB181217664_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

The analysis results presented above are preliminary,
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB181222A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23547
SUBJECT: GRB 181222A: MAXI/GSC detection
DATE:    18/12/22 07:43:15 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

A. Sakamaki, H. Negoro, M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), 
T. Mihara, S. Nakahira, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), 
T. Sakamoto, M. Serino,  S. Sugita, Y. Kawakubo, T. Hashimoto, A. Yoshida (AGU), 
N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita, T. Oeda, K. Shiraishi (Tokyo Tech), 
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai, T. Midooka (JAXA), 
Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, S. Ogawa (Kyoto U.), 
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), 
H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), 
M. Yamauchi, K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), 
K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray 
transient source at 06:44:09 UT on December 22, 2018.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (270.731 deg, -38.848 deg) = (18 02 55, -38 50 52) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.13 deg and 0.12 deg, respectively. 
The roll angle of long axis from the north direction is 132.0 deg 
counterclockwise. There is an additional systematic uncertainty of 0.1 deg
(90% containment radius).

The X-ray flux averaged over the scan was 350 +- 34 mCrab
(4.0-10.0keV, 1 sigma error).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (270.981, -38.395) deg = (18 03 55, -38 23 42) (J2000)
(R.A., Dec) = (270.687, -38.351) deg = (18 02 44, -38 21 03) (J2000)
(R.A., Dec) = (270.409, -39.448) deg = (18 01 38, -39 26 52) (J2000)
(R.A., Dec) = (270.708, -39.494) deg = (18 02 49, -39 29 38) (J2000)
There was no significant excess flux in the previous transit at 05:11 UT
with an upper limit of 20 mCrab.


GRB_name: GRB181222A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23548
SUBJECT: GRB 181222A: Fermi GBM observation
DATE:    18/12/22 17:37:52 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres (UAH) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:

"At 06:41:34.25 UT on 22 December 2018, the Fermi Gamma-Ray Burst
Monitor triggered
and located GRB 181222A (trigger 567153699 / 181222279) which was also
detected by MAXI/GSC
(Sakamaki et al., GCN 23547). The GBM on-ground location is consistent with
the MAXI position.


The angle from the Fermi LAT boresight at the GBM trigger time is 89
degrees.


The GBM light curve shows four separate pulses
with a duration (T90) of about 131 s (50-300 keV).
The time-averaged spectrum from T0-1 s to T0+151 s is
adequately fit by a Band function with Epeak = 264 +/- 32 keV,
alpha = -0.95 +/- 0.04, and beta = -1.47 +/- 0.01.

The event fluence (10-1000 keV) in this time interval is
(1.83 +/- 0.01)E-4 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+94.9 s in the 10-1000 keV band
is 74.7 +/- 0.7 ph/s/cm^2.


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


GRB_name: GRB181222B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23551
SUBJECT: GRB 181222B : Fermi GBM detection
DATE:    18/12/23 05:35:51 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P Veres (UAH) reports on behalf of the Fermi GBM Team:

"At 20:11:37.438 UT on 22 December 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181222B (trigger 567202302 / 181222841).

The on-ground calculated location, using the GBM trigger
data, is RA = 311.2, DEC = 22.9 (J2000 degrees,
equivalent to 22 h 45 m, 22 d 52 '), with an uncertainty
of 1.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 65
degrees.


The GBM light curve shows a very intense peak
with a duration (T90) of about 0.5 s (50-300 keV).
The time-averaged spectrum from T0  to T0+1.1 s is best fit by
a Band function with Epeak = 380 +/- 8 keV,
alpha = -0.74 +/- 0.01, and beta = -2.98 +/- 0.11

The event fluence (10-1000 keV) in this time interval is
(3.44 +/- 0.03)E-5 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+0.14 s in the 10-1000 keV band
is 800 +/- 6 ph/s/cm^2.

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


GRB_name: GRB181222B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23552
SUBJECT: GRB 181222B: Global MASTER Net  observations of the short bright Fermi GRB error box.
DATE:    18/12/23 10:53:54 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina,  P.Balanutsa, A.Kuznetsov, V.Vladimirov, D. Vlasenko
Lomonosov Moscow State University, SAI, Physics Department

D. Buckley, 
South African Astronomical Observatory

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

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

O. Gres, N.M. Budnev, O.Ershova, Yu.Ishmuhametov
Applied Physics Institute, Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez, F. Podesta, C.Francile
Observatorio Astronomico Felix Aguilar (OAFA)

H. Levato 
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)


MASTER-IAC robotic telescope (4 square degreess,Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to 
the  GRB181222B 107 sec after trigger time 
at 2018-12-22 20:13 24 UT in two polarizations. On our first ( 20s 
exposure )  set we  not found  optical transient within FERMI error-box (ra=311.146 dec=22.8597 r=1.6)

The real time  cover map is available
https://master.sai.msu.ru/site/master2/event.php??not=2018-12-22%2020:20:57&sat=FERMI&gcrd=(311.146d,22.8597d)&eb=1.6&trig=2018-12-22%2020:11:37&n=GRB181222.84


====================================================================

The galactic latitude b = -13 deg., longitude l = 67 deg.
The observations made on zenit distance = 62 deg.The moon (100 % bright 
part) is 25 deg. above the horizon. The distance between  moon and  object 
is 122
The sun  altitude  is -27.2 deg.
The object can be observed till sunrise at 2018-12-23 07:52:51


MASTER-Amur robotic telescope (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical 
University) was starting survey on the FERMI  GRB181222B error-box (20 
44 35 dec=+22 51 36, r=1.6)  45931 sec after notice time and 46503 sec 
after trigger time at 2018-12-23 09:06:40 UT. The 5-sigma upper limit on 
our first (60s exposure)  set is about 16.5 mag


The full information about this GRB181222B available here 
https://176.123.192.71//master2/grb.php?not=2018-12-22+20%3A21%3A08.37&sat=FERMI&gcrd=%28311.146d%2C22.86d%29&eb=1.6&trig=2018-12-22+20%3A11%3A37&n=GRB181222.84
The message may be cited.


====================================================================


The galactic latitude b = -13 deg., longitude l = 67 deg.
The observations made on zenit distance = 44 deg.
The moon (99 % bright 
part) is  8 deg. above the horizon. The distance between  moon and  object 
is 127.

  Observations started at twilight.
The sun  altitude  is -14.6 deg.
The object can be observed till 2018-12-23 14:13:01.

The observations and reduction continue.


The message may be cited.


GRB_name: GRB181222A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23553
SUBJECT: GRB 181222A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/12/24 05:13:55 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

T. Sakamoto, A. Yoshida, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 181222A (MAXI/GSC detection: Sakamaki et al., GCN Circ. 23547;
Fermi-GBM observation: Vere & Bissaldi, GCN Circ. 23548)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 06:41:33.811 UTC
on 22 December 2018. The burst signal was seen by all CGBM detectors.
Since the burst incident direction was nearly perpendicular to
the HXM detector axes, the signal in these detectors was heavily attenuated.

The burst light curve shows two main emission episodes which start
at T+1.5 sec and end at T+105.8 sec.
The T90 and the T50 durations measured by the SGM data are
98.3 +- 5.3 sec and 44.6 +- 39.7 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1229496031/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.


GRB_name: GRB181224A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23554
SUBJECT: GRB 181224A: Swift detection of a burst
DATE:    18/12/24 13:47:41 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC),
M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB),
A. Y. Lien (GSFC/UMBC) and B. Sbarufatti (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 13:36:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181224A (trigger=878911).  Swift did not slew to the burst
because of the Moon constraint.  The BAT on-board calculated location is 
RA, Dec 125.931, +6.206, which is 
   RA(J2000)  =  08h 23m 43s
   Dec(J2000) = +06d 12' 20"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curves one peak with a total
duration of about 15 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

Due to a Moon observing constraint, Swift cannot slew to the BAT
position until 08:10 UT on 2018 December 26. There will thus be no XRT
or UVOT data for this trigger before this time. 

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


GRB_name: GRB181224A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23555
SUBJECT: GRB 181224A: Swift-BAT refined analysis
DATE:    18/12/25 03:17:55 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), A. Melandri (INAF-OAB),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+450 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 181224A (trigger #878911)
(Melandri et al., GCN Circ. 23554).  The BAT ground-calculated position is
RA, Dec = 125.949, 6.194 deg which is
  RA(J2000)  =  08h 23m 47.7s
  Dec(J2000) = +06d 11' 39.9"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 80%.

The mask-weighted light curve shows a single-peaked structure that starts at
~ T-12 s, peaks at ~ T+1 s, one ends at ~ T+4 s. T90 (15-350 keV) is
12.5 +- 4.2 sec (estimated error including systematics).

The time-averaged spectrum from T-12.04 to T+3.30 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.27 +- 0.20.  The fluence in the 15-150 keV band is 4.9 +- 0.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.48 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/878911/BA/


GRB_name: GRB181222B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23556
SUBJECT: IPN Triangulation of extremely bright short GRB 181222B
DATE:    18/12/25 10:29:28 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team, report:

The short-duration, extremely bright GRB 181222B (Veres, GCN 23551)
was detected by Fermi (GBM trigger 567202302) and Konus-Wind
at about 72697 s UT (20:11:37).

We have triangulated it to a Konus-GBM annulus centered at 
RA(2000)=294.324 deg (19h 37m 18s) Dec(2000)=-23.694 deg (-23d 41' 39"), 
whose radius is 51.089 +/- 0.097 deg (3 sigma). The annulus reduces the 
area of the 3 sigma Fermi-GBM final position by about a factor of 130.

This annulus may be improved.

A triangulation map is posted at
ttp://www.ioffe.ru/LEA/GRBs/GRB181222_T72694/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB181222B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23557
SUBJECT: Konus-Wind observation of GRB 181222B
DATE:    18/12/25 10:36:09 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration, extremely bright GRB 181222B
(Fermi-GBM detection: Veres, GCN Circ. 23551;
IPN triangulation: Svinkin et al., GCN Circ. 23556)
triggered Konus-Wind at T0=72694.563 s UT (20:11:34.563).

The burst light curve shows a single pulse
which starts at about T0 and has a total duration of ~2.1 s.
The emission is seen up to ~15 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181222_T72694/

As observed by Konus-Wind, the burst
had a fluence of 3.70(-0.17,+0.18)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.166 s,
of 2.72(-0.25,+0.26)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+0.512 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.52(-0.08,+0.08),
the high energy photon index beta = -2.95(-0.30,+0.20),
the peak energy Ep = 365(-26,+27) keV
(chi2 = 53/56 dof).

Among ~300 bursts from the Konus catalog of short GRBs
(Svinkin et al., ApJS 224, 10, 2016), GRB 181222B is within top 2%
in the terms of 16-ms peak energy flux and within top 2% in the terms
of the total energy fluence, both in the 20 keV - 10 MeV range.

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


GRB_name: GRB181222B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23558
SUBJECT: GRB 181222B: Global MASTER Net observations of short bright Fermi GRB
DATE:    18/12/25 11:34:42 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina,  P.Balanutsa,
A.Kuznetsov, D. Vlasenko, D.Kobtsev
Lomonosov Moscow State University, SAI

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley,
South African Astronomical Observatory

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

O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev,
Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko,
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

H. Levato
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

The Global MASTER network continues to inspect error box of the short
bright gamma-ray burst GRB 181222B (Veres, GCN #23551; Lipunov et al.,
GCN #23552)

MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,
vol. 2010, 30L) located in Spain (IAC Teide Observatory)
started inspect survey of  Fermi GRB18122B   IPN
error-box (Svinkin et al., GCN #23556)
36801 sec after notice time and 36801 sec after trigger time
at 2018-12-24 19:07:42 UT.
  There are 479 galaxies in IPN localization.

MASTER auto-detection system found optical transient:

MASTER OT J204928.79+245744.0 detection.

MASTER-IAC auto-detection system discovered OT source at
(RA, Dec)=20h 49m 28.79s +24d 57m 44.0s on 2018-12-24.81773 UT.
The OT unfiltered magnitude is 16.9m (limit 18.6m).

The OT is seen in 2 images. There is no minor planet at this place.
We have reference image without OT on 2018-08-02.04970 UT with 18.7m unfiltered magnitude limit .
There is red start in PanSTARR (rmag=21.7) and SDSS.9 (r=21.9)
Spectral observations are required.


Observations started at twilight.The sun  altitude was -11.5 deg.
The observations made on zenit distance = 29 deg.
The moon (94 % bright part) below the horizon
The altitude of the Moon is -14 deg.
The object can be observed till 2018-12-25 00:54:38.
The galactic latitude b = -60 deg., longitude l = 98 deg.

MASTER-Amur robotic telescope  located in Russia (Blagoveshchensk State
Pedagogical University) was pointed to the  FERMI GRB181222B 46503 sec
after trigger time at 2018-12-23 09:06:40 UT, with upper limit up to  17.8
mag. Observations started at twilight.  The observations began at zenit
distance = 44 deg. The sun  altitude  is -14.2 deg.

MASTER-Tunka robotic telescope  located in Russia (Applied Physics
Institute, Irkutsk State University) was pointed to the  FERMI
GRB181222B 52255 sec after trigger time at 2018-12-23 10:42:32 UT, with
upper limit up to  18.6 mag. Observations started at twilight.  The
observations began at zenit distance = 44 deg. The sun  altitude  is -14.5
deg.


The cover map is available at
https://master.sai.msu.ru/site/master2/observ.php?id=890715


The message may be cited.


GRB_name: GRB181222A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23559
SUBJECT: Konus-Wind observation of GRB 181222A
DATE:    18/12/25 11:35:12 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 181222A
(MAXI/GSC detection: Sakamaki et al., GCN Circ. 23547;
Fermi/GBM observation: Veres & Bissaldi, GCN Circ. 23548;
CGBM detection: Sakamoto et al., GCN Circ. 23553)
triggered Konus-Wind at T0=24090.989 s UT (06:41:30.989).

The burst light curve shows a multipeaked structure
started at ~T0-1.3 s with a total duration of ~171.5 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.97(-0.33,+0.32)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+94.208 s,
of 6.71(-0.66,+0.66)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+146.688 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.05(-0.08,+0.08),
the high energy photon index beta = -1.90(-0.12,+0.09),
the peak energy Ep = 570(-100,+133) keV
(chi2 = 79/84 dof).

The spectrum near the maximum count rate
(measured from T0+93.440 to T0+96.000 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.87(-0.06,+0.06),
the high energy photon index beta = -2.01(-0.10,+0.08),
the peak energy Ep = 850(-114,+136) keV
(chi2 = 115/77 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181222_T24090/

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


GRB_name: GRB181225A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23560
SUBJECT: GRB 181225A: AGILE/MCAL detection of a burst
DATE:    18/12/25 16:22:35 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A.
Argan, M. Cardillo, C. Casentini, Y. Evangelista, G. Piano (INAF/IAPS), F.
Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli,
V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi
(INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN
Trieste), A. Giuliani (INAF/IASF-Mi),
report on behalf of the AGILE Team:

The AGILE Mini-CALorimeter (MCAL) detected a short burst at T0 = 2018-12-25
11:44:11.76 +/- 0.01 s (UTC). The event lasted about 1.2 s and released a
total number of ~1580 counts in the detector (in the 0.4-100 MeV energy
range), above an average background rate of 750 counts / s.

Further analysis is still in progress.

The AGILE-MCAL detector has a full solid angle acceptance, and is
operational in the range 0.4 - 100 MeV.


GRB_name: GRB181225A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23561
SUBJECT: GRB 181225A: Fermi-LAT Detection
DATE:    18/12/25 21:42:26 GMT
FROM:    Makoto Arimoto at Tokyo Inst of Tech  <arimoto@hp.phys.titech.ac.jp>

M. Arimoto (Kanazawa Univ.), M. Palatiello (University of Udine and
INFN Trieste),
F. Longo (University and INFN, Trieste), D. Kocevski (NASA/MSFC),
E. Bissaldi (Politecnico and INFN, Bari), G. Vianello (Stanford), and
E. Moretti (IFAE) report on behalf of the Fermi-LAT team:

On December 25, 2018, Fermi-LAT detected high-energy emission from GRB 181225A,
which was also detected by Fermi-GBM (trigger 567431055 / 181225489)
and AGILE-MCAL (A. Ursi et al., GCN 23560).
The best LAT on-ground location is found to be

RA, Dec = 348.07, -9.48 (degrees, J2000)

with an error radius of 0.13 deg (90% containment, statistical error only).
This was 44 deg from the LAT boresight at the time of the GBM trigger:

T0 =  11:44:10.5 UT.

The data from the Fermi-LAT show a significant increase
in the event rate after the GBM trigger that is temporally correlated with the
GBM emission with high significance.
The photon flux above 100 MeV in the time interval 0-1000 s after the
GBM trigger is (2.4 +/- 0.5) E-5 ph/cm2/s, the one above 1 GeV is (1.5
+/- 0.5)E-5 ph/cm2/s.

The estimated photon index above 100 MeV is -2.24 +/- 0.18.

The highest-energy photon is a 13 GeV event which is observed ~4 seconds
after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is
Michele Palatiello (michele.palatiello@ts.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: GRB181225A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23562
SUBJECT: GRB 181225A: Fermi GBM detection
DATE:    18/12/26 03:56:19 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

S.Poolakkil(UAH), C. Meegan (UAH) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:

"At 11:44:10.53 UT on 25 December 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181225A (trigger 567431055/ 181225489),
which was also detected by the Fermi LAT (M. Arimoto et al. 2018, GCN
23561).
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 44 degrees.

The GBM light curve shows multiple peaks
with a duration (T90) of about 41.5 s (50-300 keV).
The time-averaged spectrum from T0-2.0 s to T0+36.8 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.04 +/- 0.10 and
the cutoff energy, parameterized as Epeak, is 1887 +/- 966 keV.

The event fluence (10-1000 keV) in this time interval is
(5.569 +/- 0.370)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.54 s in the 10-1000 keV band
is 3.74 +/- 0.19 ph/s/cm^2.

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


GRB_name: GRB181225A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23563
SUBJECT: GRB 181225A: Swift ToO observations
DATE:    18/12/26 09:31:38 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/LAT GRB 181225A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020849

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB181225A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23564
SUBJECT: GRB 181225A: Global MASTER Net optical observations 
DATE:    18/12/26 11:36:28 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

D.Kobtsev, V. Yurkov, A. Gabovich, Yu. Sergienko,
(Blagoveschensk State Pedagogical University, Russia)

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina,  P.Balanutsa, A.Kuznetsov, D. Vlasenko,
(Lomonosov Moscow State University, SAI)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
(The Instituto de Astrofisica de Canarias)

D. Buckley (South African Astronomical Observatory)

A. Tlatov, V.Senik,  D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory)

O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev (API, Irkutsk State University)

R. Podesta, C.Lopez, F. Podesta
(Observatorio Astronomico Felix Aguilar of San Juan National University, Argentina)

H. Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio of San 
Juan National University, Argentina)


Global MASTER-Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)
was pointed to LAT GRB 181225A (Arimoto et al. GCN 23561, first detected by AGILE in GCN 23560 Ursi et al. )
by MASTER-SAAO (at 2018-12-25 21:08:21UT, alert_altitude=9deg.) and by 
MASTER-IAC.

MASTER-IAC robotic telescope, located in Spain (IAC Teide Observatory), 
was pointed to the LAT GRB181225.49 ( 23h 12m 16.80s , -09d 28m 48.00s, R=0.13)
34022 sec after trigger time at 2018-12-25 21:11:14 UT, with upper limit up to 19.9 mag.

We didn't find OT brighter 19.9 (unfiltered).

The observations started at zenit distance = 60 deg. The sun altitude was -38.0 deg.
The galactic latitude b = -60 deg., longitude l = 98 deg.

Updated in real-time cover map and discovered OT will be  available here:
https://master.sai.msu.ru/site/master2/observ.php?id=893244

The observation and reduction will be continued.

The message may be cited.


GRB_name: GRB181225A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23565
SUBJECT: GRB 181225A: Swift observations and X-ray candidate afterglow
DATE:    18/12/26 19:34:17 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

V. Dâ€™Elia (SSDC), A. Dâ€™Ai (INAF-IASFPA), and M. H. Siegel (PSU) report on behalf of the Swift team

Swift-XRT and Swift-UVOT have performed follow-up observations of the AGILE-, GBM- and LAT-detected burst GRB 181225A (Ursi et al., GCN Circ. 23560; Arimoto et al. GCN Circ., 23561; Poolakkil et al., GCN Circ. 23562). The XRT total exposure time is 5 ks. The data were collected ~15 hr after the trigger, and are entirely in Photon Counting (PC) mode. Swift-UVOT data were collected simultaneously with the XRT data in UVOTâ€™s u, v and white filters. 

Two sources are detected in the XRT field of view, at the border of the LAT error circle (0.13 deg, 90% containment, statistical error only, Arimoto et al. GCN Circ. 23561). 

The first one is located at:
RA(J2000)   =  23h 12m 12.2s
Dec(J2000) = -09d 19â€™ 29.5â€
and is 0.156 deg away from the best LAT localization. Its count rate is (2.5 +/- 0.3)E-2 cts/s. However, its position is coincident with SDSSJ23122-0919, a radio source with a ROSAT X-ray counterpart, and thus it is likely unrelated with the X-ray afterglow of GRB181225A. 

This source is detected in all three UVOT filters with magnitudes and colors roughly consistent with archival values.

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

white          55175        61751         1213      17.89+/-0.03
u                54338        66054         1868      19.45+/-0.15
v                56013        62624         1373      18.56+/-0.12

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).


The second X-ray source is located at: 
RA(J2000)   = 23h 12m 51.5s 
Dec(J2000) = -09d 30â€™ 08.9â€
and is 0.144 deg away from the LAT localization. Its count rate is (3.7 +/-1.1)E-3 cts/s. This source is not related with any known astrophysical object, and it is thus a candidate X-ray afterglow for GRB181225A. This source was too far off the pointing to be imaged by UVOT. No new source is detected in the UVOT images. Given its faintness, low significance (S/N ~3), and no current information on variability in X-ray, we cannot confirm at the present stage if it is the X-ray afterglow. 

This is an official product of the Swift team.


GRB_name: GRB181222A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23566
SUBJECT: GRB 181222A: AstroSat CZTI detection
DATE:    18/12/27 09:35:44 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 181222A, which was also detected by MAXI/GSC (Negoro H. et al., GCN 23547), Fermi/GBM (Veres P. et al., GCN 23548), CALET (Sakamoto T. et al., GCN 23553) and Konus-Wind (Kozlova A. et al., GCN 23559).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 06:43:09.500 UT. The measured peak count rate is 1720 cts/s above the background in combined data of four quadrants, with a total of 14364 cts. The local mean background count rate was 522 cts/s. Using cumulative rates, we measure a T90 of 117 s. In preliminary analysis, we find that 1258 compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB181225A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23567
SUBJECT: GRB 181225A: Insight-HXMT/HE detection
DATE:    18/12/27 14:05:53 GMT
FROM:    QiBin Yi at IHEP, HXMT  <yiqb@ihep.ac.cn>

Q. B. Yi, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2018-12-25T11:44:10.000 (T0), the Insight-HXMT/HE detected 
GRB 181225A (trigger ID: HEB181225489) in a routine search of the data, 
which was also triggered by by AGILE/MCAL (A. Ursi et al.,GCN23560)ã€
Fermi/LAT (M. Arimoto et al., GCN23561) and Fermi/GBM (S.Poolakkil., GCN23562).

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 1.23 s measured from T0+0.46 s. 
The 50-ms peak rate, measured from T0+1.208 s, is 2963.2 cnts/s. 
The total counts from this burst 2350.8 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB181225489_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
GRB mode with the energy range of about 200-3000 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB181222B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23568
SUBJECT: GRB 181222B: Swift ToO observations
DATE:    18/12/27 16:22:51 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi+MASTER GRB 181222B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020850

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi+MASTER event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB181227A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23569
SUBJECT: GRB 181227A: Fermi GBM detection
DATE:    18/12/27 22:06:13 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

E. Bissaldi (Politecnico & INFN Bari) and P. Veres (UAH)
report on behalf of the Fermi GBM Team:

"At 06:17:00.50 UT on 27 December 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181227A (trigger 567584225 / 181227262).

The on-ground calculated location, using the GBM trigger
data, is

RA, Dec = 24.2, -56.1

(J2000 degrees), with an uncertainty of 1 degree (radius, 1-sigma
containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32]).

The angle from the Fermi LAT boresight at the GBM trigger time is 110
degrees.

The GBM light curve consists of two peaks
with a duration (T90) of about 13 s (50-300 keV).
The time-averaged spectrum from T0-0.3 s to T0+19.8 s is
best fit by a Band function with Epeak = 85 +/- 1 keV,
alpha = -0.33 +/- 0.02, and beta = -3.08 +/- 0.05.

The event fluence (10-1000 keV) in this time interval is
(6.85 +/- 0.05)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+8.9 s in the 10-1000 keV band
is 110.5 +/- 1.2 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(27dec18):  Per author's request, the alpha value
in the third paragraph was changed from "0.33" to "-0.33".]


GRB_name: GRB181228A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23570
SUBJECT: GRB 181228A: Swift detection of a burst
DATE:    18/12/28 03:07:38 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

M. J. Moss (George Washington University), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU),
A. Y. Lien (GSFC/UMBC) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 02:53:17 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181228A (trigger=879909).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 49.831, +13.195, which is 
   RA(J2000)  =  03h 19m 19s
   Dec(J2000) = +13d 11' 42"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows multiple overlapping peaks
with a duration of about 25 sec.  The peak count rate
was ~7000 counts/sec (15-350 keV), at ~13 sec after the trigger. 

The XRT began observing the field at 02:54:40.1 UT, 82.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 49.8114,
13.2000 which is equivalent to:
   RA(J2000)  = 03h 19m 14.75s
   Dec(J2000) = +13d 12' 00.1"
with an uncertainty of 2.6 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.  We
cannot determine whether the source is fading at the present time. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 2.5 s image was 5.46e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of nominal 150.000 seconds with the White
filter starting 93 seconds after the BAT trigger. No credible afterglow
candidate has been found in the initial data products. Data from the 2.7'x2.7'
sub-image are not available at this time. 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 0.51. 

Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23571
SUBJECT: GRB 181228A: KAIT Optical Upper Limit
DATE:    18/12/28 04:15:53 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 181228A (Moss et al.,
GCN 23570) starting at 03:03:30 UT, 613 s after the burst.
Observations were performed with an automatic sequence in the
clear (roughly R), V, and I filters, and the exposure time was 20 s
per image. We do not detect any optical afterglow candidate within
the XRT position error circle (Moss et al., GCN 23570),
neither in single image, nor in the co-add images.
The typical limiting magnitude of our single clear image is about
18.5 mag calibrated to the Pan-STARRS1 catalog.


GRB_name: GRB181225A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23572
SUBJECT: GRB 181225A: KAIT Follow-Up Observations with Upper Limit
DATE:    18/12/28 04:44:24 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng, Keto Zhang, Alexei V. Filippenko, and Sergiy Vasylyev
(UC Berkeley) report on behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, observed the field of the AGILE-, GBM- and
LAT-detected burst GRB 181225A (Ursi et al., GCN Circ. 23560;
Arimoto et al. GCN Circ., 23561; Poolakkil et al., GCN Circ. 23562).
More than 250 galaxies near the Fermi/LAT localization (Arimoto et al.
GCN Circ., 23561) were selected from the Glade catalog
(http://aquarius.elte.hu/glade/) according to
their priority score. On 2018 Dec. 26 UT, KAIT observed 82 of them having
top-priority scores, with each clear-filter exposure time being 60 s.
The first image was taken at 01:47:23 UT, about 14.05 hr after
AGILE/MCAL trigger time, and the last image at 04:24:11 UT.

For the two Swfit/XRT sources reported by D'Elia (GCN 23565), the first
one was not covered by KAIT images. The second source, which was considered
to be a candidate X-ray afterglow for GRB181225A, was covered by one
of the KAIT image taken at 03:46:38 UT (namely 16.04 hours after
AGILE/MCAL trigger. However, we do not detect any optical afterglow
candidate
around the second XRT source, with limiting mag ~19.0 calibrated to the
Pan-STARRS1 catalog.


GRB_name: GRB181225A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23573
SUBJECT: GRB 181225A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/12/28 05:46:14 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU),
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The hard GRB 181225A (AGILE/MCAL detection: Ursi et al., GCN Circ. 23560;
Fermi-LAT detection: Arimoto et al., GCN Circ. 23561;
Fermi GBM detection: Poolakkil et al., GCN Circ. 23562)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 11:44:11.011 UTC
on 25 December 2018. The burst signal was seen by all CGBM detectors.

The burst light curve shows the initial hard pulse which starts
at T-0.6 sec and ends at T+1.1 sec, followed by a weaker and softer tail
seen up to T+10.8 sec.
The T90 and the T50 durations measured by the SGM data are
10.6 +- 0.8 sec and 7.5 +- 0.8 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1229773383/

Although the measured durations put this GRB in the long class,
its hard initial pulse which has a duration of ~1.7 sec and
the weaker and softer tail may imply that this GRB is in fact
a short GRB with extended emission or it is similar to the famous
"long-short" GRB 060614 (Gehrels et al. 2006, Nature,
444, 1044: https://www.nature.com/articles/nature05376).

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.


GRB_name: GRB181228A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23574
SUBJECT: GRB 181228A: Enhanced Swift-XRT position
DATE:    18/12/28 06:34:33 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1212 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 181228A, 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 = 49.81214, +13.20208 which is equivalent
to:

RA (J2000): 03h 19m 14.91s
Dec (J2000): +13d 12' 07.5"

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: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23575
SUBJECT: GRB 181228A: REM NIR detection
DATE:    18/12/28 09:35:37 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo, S.Covino, D. Fugazza, A. Melandri (INAF-OAB), on behalf of the REM team, report:

We observed the field of GRB 181228A (Moss et al. GCN 23570) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile). 
The observations were performed starting on 2018 December 28 at 02:54:10 UT (i.e. 53 seconds after the burst) and were carried in the g, r, i, z, J, H 
and K bands. 

In the first set of NIR images (carried out in the H band) we detect an uncatalogued, fading source at the following position: 

RA (J2000): 03:19:15.05
Dec (J2000): +13:12:06.7

+/- 0.5". 

This position is consistent with the enhanced XRT position reported by Beardmore et al. (GCN 23574). The NIR source we detect is not present in the 
2MASS catalogue. We propose this source as the NIR afterglow of GRB 181228A.  

From preliminary photometry we estimate the following magnitudes:

H = 14.3 +/- 0.1 at t-t0 = 122 s
H = 16.4 +/- 0.3 at t-t0 = 601 s

(Vega; calibrated against the 2MASS catalogue). At the same epochs, the source is not detected in the optical down to a 3sigma limiting magnitude of 
r ~ 18.0 (AB; calibrated against the pan-STARRS catalogue). This is consistent with the early optical non-detection reported by Zheng & Filippenko 
(GCN 23571).


GRB_name: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23576
SUBJECT: GRB 181228A: Global MASTER Net  OT detection 
DATE:    18/12/28 09:46:03 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, N.Tiurina, E. Gorbovskoy, V.Kornilov,  P.Balanutsa,
A.Kuznetsov, D. Vlasenko, D.Kobtsev
(Lomonosov Moscow State University, SAI),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar),

H. Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio of San 
Juan National University, Argentina)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
(The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

A. Tlatov, V.Senik,  D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

O. Gress, N.M. Budnev, S. Yazev, O. Chuvalaev (Irkutsk State University, API)

V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)


MASTER-OAFA robotic telescope (Global MASTER Net  http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Argentina (OAFA observatory of San Juan National University) was pointed to the 
GRB181228A (Moss et al., GCN #23570) 26 sec after notice time and 47 sec after 
trigger time at 2018-12-28 02:54:05 UT. On our first (10s exposure)  set we 
found 1 optical transient within SWIFT XRT error-box  (Beardmore et al., GCN 
#23574) brighter than 17.5.


  T-Tmid      Date      Time     Expt.        Ra                Dec    Mag
    s                   UTC       s 
---------|-------------------|------|-----------------|-----------------|-------
     52   2018-12-28 02:54:05     10  ( 03h 19m 14.80s , +13d 12' 02".80 ) 17.0

The 5-sigma upper limit has been about 17.5 mag . Coordinate error ~2".

The galactic latitude b = -35 deg., longitude l = 170 deg.
The observations made on zenit distance = 49 deg.The moon (64 % bright part) 
below the horizon (The altitude of the Moon is -14 deg. ).
The sun  altitude  is -29.6 deg.
The object can be observed till 2018-12-28 06:59:09
The message may be cited.


GRB_name: GRB181227A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23577
SUBJECT: IPN Triangulation of GRB 181227A (long)
DATE:    18/12/28 10:27:23 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

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

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

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

and

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

The long-duration GRB 181227A
(Fermi-GBM detection: Bissaldi & Veres, GCN Circ. 23569)
was detected by Fermi (GBM trigger 567584225), Konus-Wind,
INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and Swift (BAT)
at about 22620 s UT (06:17:00).
The burst was detected by Swift (BAT) during the slew and
no event data were captured (Sakamoto, Lien, and Pal'shin, priv. comm.).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    29.889 (01h 59m 33s) -53.321 (-53d 19' 14")
  Corners:
    30.664 (02h 02m 39s) -52.621 (-52d 37' 16")
    30.861 (02h 03m 27s) -53.105 (-53d 06' 19")
    27.501 (01h 50m 00s) -54.693 (-54d 41' 35")
    27.344 (01h 49m 22s) -54.208 (-54d 12' 30")
  ---------------------------------------------
The error box area is about 1.13 sq. deg, and its maximum
dimension is 2.79 deg (the minimum one is 27.84 arcmin).
The Sun distance was about 84 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB181227_T22619/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23578
SUBJECT: GRB 181228A: Global MASTER-Net  OT detection
DATE:    18/12/28 11:56:32 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

N.Tyurina, V. Lipunov, E. Gorbovskoy, V.Kornilov,  P.Balanutsa,
A.Kuznetsov, D. Vlasenko, D.Kobtsev
Lomonosov Moscow State University, SAI

R. Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

H. Levato
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, South African Astronomical Observatory

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

O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko,
Blagoveschensk Educational State University, Blagoveschensk


MASTER-OAFA robotic telescope (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan 
National University) was pointed to the  GRB181228A (Moss et al., 
GCN #23570) 26 sec after notice 
time and 47 sec after trigger time at 2018-12-28 02:54:05 UT. On our first 
(10s exposure)  set we  found 1 optical transient within SWIFT 
XRT error-box  (Beardmore et al., GCN #23574) brighter than 17.5.


  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
    s                   UTC         s 
---------|---------------------|-------|-----------------|-----------------|-------
     52   2018-12-28 02:54:05       10   ( 03h 19m 14.80s , +13d 12' 02".8 )    17.0

The 5-sigma upper limit has been about 17.5 mag . Coordinate error ~1".

The galactic latitude b = -35 deg., longitude l = 170 deg.
The observations made on zenit distance = 49 deg.The moon (64 % bright 
part) below the horizon (The altitude of the Moon is -14 deg. ).
The sun  altitude  is -29.6 deg.
The object can be observed till 2018-12-28 06:59:09
The message may be cited.


GRB_name: GRB181228A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23579
SUBJECT: GRB 181228A: Fermi GBM observation
DATE:    18/12/28 14:35:02 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari) and P. Veres (UAH)
report on behalf of the Fermi GBM Team:


"At 02:53:14.96 UT on 28 December 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181228A (trigger 567658399 / 181228120),
which was also detected by the Swift/BAT (Moss et al. 2018, GCN 23570).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 72 degrees.

The GBM light curve consists of a two-peaked emission episode
with a duration (T90) of about 18 s (50-300 keV).
The time-averaged spectrum from T0 to T0+19 s is
best fit by a Band function with Epeak = 182 +/- 8 keV,
alpha = -0.82 +/- 0.03, and beta = -2.25 +/- 0.07.

The event fluence (10-1000 keV) in this time interval is
(2.56 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+15.6 s in the 10-1000 keV band
is 16.0 +/- 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: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23580
SUBJECT: GRB 181228A: TSHAO optical upper limit
DATE:    18/12/28 16:49:22 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), I. Reva (FAPHI), A. Pozanenko (IKI), E. Mazaeva (IKI), 
S. Belkin (IKI), A. Kusakin (FAPHI),  M. Krugov (FAPHI) report on behalf 
of larger GRB follow-up collaboration:

We observed the field of GRB 181228A (Moss et al., GCN 23570; 
Beardmoreet al., GCN 23574) with Zeiss-1000 1-m telescope of Tien Shan 
Astronomical Observatory starting on Dec. 28 (UT) 13:35:51.  We do not 
detected the OT   (D'Avanzo et al., GCN 23574; Lipunov et al. GCN 
23576). Preliminary photometry of the field is following.

Date       UT start t-T0    Filter Exp.   OT   Err. UL
                     (mid, days) (s)

2018-12-28 13:35:51 0.46359 R      21*120 n/d  n/d  21.7

The photometry is based on nearby USNO-B1.0 star
USNO-B1.0_id R2
1032-0046066 16.66


GRB_name: GRB181228A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23581
SUBJECT: GRB 181228A: Swift/UVOT Upper Limits
DATE:    18/12/28 16:53:43 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 181228A: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and M. J. Moss (George Washington University)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181228A
93 s after the BAT trigger (Moss et al., GCN Circ. 23570).
No optical afterglow consistent with the XRT position
(Moss et al. GCN Circ. 23570)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC            93          243          147         >20.4
u_FC               305          555          246         >20.6
white               93         1354          373         >21.0
v                  634         1404           97         >19.1
b                  561         1330           78         >20.5
u                  305         1305          304         >20.5
w1                 684         1280           39         >18.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.51 in the direction of the burst
(Schlegel et al. 1998). 


GRB_name: GRB181222B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23582
SUBJECT: GRB 181222B: Swift follow-up observations of MASTER optical transient J204928.79+245744.0
DATE:    18/12/28 17:36:50 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

A. Tohuvavohu (PSU), A. D'Ai (INAF-IASFPA), M. Siegel (PSU), J.A.
Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester),
A. Melandri (INAF-OAB), and P.A. Evans (U. Leicester) report on behalf
of the Swift-XRT and Swift-UVOT teams:

Swift has performed follow-up observations of the MASTER optical
transient J204928.79+245744.0  (V. Lipunov et al. GCN Circ. 23588),
within the IPN localization region of Fermi/GBM and Konus detected GRB
181222B (P. Veres GCN Circ. 23551, D. Svinkin et al. GCN Circ. 23556).

Swift/XRT collected 3.9 ks of Photon Counting (PC) mode data between
T0+414.9 ks and T0+427.0 ks. No X-ray source was detected at the MASTER
position with an upper limit of 2.4 e-3 ct s^-1.

Two uncatalogued X-ray sources have been detected in the field during
this observation.  Both sources are below the RASS limit and show no
definitive signs of fading. Given the large localization region of this
burst and the amount of time elapsed between the GRB and these
observations, we believe it unlikely that these X-ray sources are
related to the GRB.
Details of the sources are given below:

Source 1:
 RA (J2000): 312.2708 = 20:49:52.88
 Dec (J2000): +25.0419= +25:02:30.9
 Error: 2.5 arcsec (radius, 90% conf.)
 Count-rate (9.9 [+2.0, -1.9])e-3 ct s^-1
 Distance: 7.2 arcminutes from MASTER position.
 Flux: (2.3 [+0.5, -0.4])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000):  312.3700  =  20:49:28.81
  Dec (J2000): +24.9769  =  +24:58:37.0
  Error: 7.7 arcsec (radius, 90% conf.)
  Count-rate: (3.03 [+1.21, -0.97])e-3 ct s^-1  
  Distance: 53 arcsec from MASTER position.
  Flux: (1.22 [+0.49, -0.39])e-13 erg cm^-2 s^-1 (observed, 0.3-10
keV).

Swift/UVOT began observing the field in the White filter 414 ks after
the GRB trigger. We do not find any optical source at the MASTER
position, with an upper limit of 21.48 +/- 0.22 magnitude (AB) in a 
3094 second exposure.  This magnitude is not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.24 in the direction of
the burst (Schlegel et al. 1998).

The results of the XRT-team automatic analysis of the XRT observations,

including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020850/.

This circular is an official product of the Swift team.


GRB_name: GRB181228A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23583
SUBJECT: GRB 181228A: Swift-BAT refined analysis
DATE:    18/12/28 18:56:14 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
C. B. Markwardt (GSFC), M. J. Moss (GWU),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 181228A (trigger #879909)
(Moss et al., GCN Circ. 23570).  The BAT ground-calculated position is
RA, Dec = 49.831, 13.212 deg which is
  RA(J2000)  =  03h 19m 19.5s
  Dec(J2000) = +13d 12' 44.0"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 30%.

The mask-weighted light curve shows a multi-peaked structure. The main
structure starts at ~T-4 s and ends at ~T+20 s, with the highest peak
occurs at ~ T+13 s. After the main pulse, there is another much weaker
pulse that starts at ~ T+200 s and ends at ~T+340 s. T90 (15-350 keV)
is 257.3 +- 102.5 sec (estimated error including systematics).

The time-averaged spectrum from T-4.0 to T+337.9 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.45 +- 0.06.  The fluence in the 15-150 keV band is 1.0 +- 0.03 x 10^-05 erg/cm2.
The 1-sec peak photon flux measured from T+13.08 sec in the 15-150 keV band
is 9.5 +- 0.5 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/879909/BA/


GRB_name: GRB181228A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23584
SUBJECT: GRB 181228A: Swift-XRT refined Analysis
DATE:    18/12/28 20:51:37 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne
(U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P.
D'Avanzo (INAF-OAB) and M.J. Moss report on behalf of the Swift-XRT
team:

We have analysed 6.2 ks of XRT data for GRB 181228A (Moss et al. GCN
Circ. 23570), from 88 s to 58.6 ks after the  BAT trigger. The data
comprise 405 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 23574).

The late-time light curve (from T0+12.9 ks) can be modelled with a
power-law decay with a decay index of alpha=0.95 (+0.29, -0.28).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.60 (+/-0.05). The
best-fitting absorption column is  3.30 (+0.28, -0.27) x 10^21 cm^-2,
in excess of the Galactic value of 2.9 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.80 (+0.20, -0.19)
and a best-fitting absorption column of 5.3 (+1.4, -1.2) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.6 x 10^-11 (6.8 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.3 (+1.4, -1.2) x 10^21 cm^-2
Galactic foreground: 2.9 x 10^21 cm^-2
Excess significance: 3.2 sigma
Photon index:      1.80 (+0.20, -0.19)

If the light curve continues to decay with a power-law decay index of
0.95, 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 5.7 x
10^-13 (8.4 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/00879909.

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


GRB_name: GRB181227A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23586
SUBJECT: GRB 181227A: Global MASTER Net  oprtical inspection
DATE:    18/12/29 09:02:21 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

E. Gorbovskoy, V. Lipunov, N.Tiurina,  V.Kornilov, 
P.Balanutsa, A.Kuznetsov, D. Vlasenko, D.Kobtsev
(Lomonosov Moscow State University, SAI),

R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix 
Aguilar),

H. Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio of San Juan 
National University, Argentina)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
(The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

A. Tlatov, V.Senik,  D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

O. Gress, N.M. Budnev, S. Yazev, O. Chuvalaev (Irkutsk State University, API)

V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State 
University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L)  located in South Africa (South African Astronomical 
Observatory) was pointed to the  FERMI and IPN  GRB181227A (E. Bissaldi et 
al. GCN  23569, Hurley et al  23577 44386 sec after trigger time at 
2018-12-27 18:36:46 UT, with upper limit up to  20.4 mag. Observations 
started at twilight, immediately after sunset.  The observations began at 
zenit distance = 25 deg. The sun  altitude  is -9.8 deg.

MASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) was 
pointed to the  FERMI and IPN  GRB181227A  47842 sec after trigger time at 
2018-12-27 19:34:23 UT, with upper limit up to  18.0 mag. The observations 
began at zenit distance = 85 deg. The sun  altitude  is -17.0 deg.

MASTER-OAFA robotic telescope  located in Argentina (OAFA observatory of 
San Juan National University) was pointed to the  FERMI and IPN 
GRB181227A 1 days 7760 sec after trigger time at 2018-12-28 08:26:20 UT, 
with upper limit up to  20.5 mag. Observations started at twilight.  The 
observations began at zenit distance = 83 deg. The sun  altitude  is -12.7 
deg.

The galactic latitude b = -60 deg., longitude l = 98 deg.


Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=894852

No OT found yet.

The message may be cited.

[GCN OPS NOTE(29dec18): Per author's request, the name of the GRB in the SUBJECT-line
was changed from "GRB 181228A" to "GRB 181227A".]


GRB_name: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23588
SUBJECT: GRB 181228A: Xinglong-2.16m optical upper limit
DATE:    18/12/29 13:31:29 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

Z.P. Zhu, L.P. Xin, D. Xu, J.B. Zhang (NAOC), X. Zhang, J.H. Liu (XAO) 
report:

We observed the field of GRB 181228A (Moss et al., GCN 23570) using the 
2.16-m telescope located at Xinglong, Hebei, China, equipped with the 
BFOSC camera. We obtained 6x300s and 2x600s frames in I-band, starting 
at 13:04:00 UT on 2018-12-28, i.e., 10.18 hrs after the BAT trigger.

The afterglow of GRB 181228A  (e.g., Moss et al., GCN 23570; D'Avanzo et 
al., GCN 23575; Lipunov et al., GCN 23576) is not detected in our 
stacked image, down to a limiting magnitude of ~20.5 mag, calibrated 
with the nearby PanSTARRS field.


GRB_name: GRB181227A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23589
SUBJECT: Konus-Wind observation of GRB 181227A
DATE:    18/12/29 22:21:42 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, bright GRB 181227A
(Fermi-GBM detection: Bissaldi & Veres, GCN Circ. 23569;
IPN triangulation: Hurley et al., GCN Circ. 23577)
triggered Konus-Wind at T0=22619.317 s UT (06:16:59.317).

The burst light curve shows a single emission episode
which starts at ~T0-0.5 s and has a total duration of ~17 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 5.91(-0.12,+0.12)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+8.944 s,
of 1.39(-0.15,+0.16)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+18.688 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.66(-0.07,+0.07),
the high energy photon index beta = -3.53(-0.24,+0.18),
the peak energy Ep = 93(-2,+2) keV
(chi2 = 72/96 dof).

The spectrum near the maximum count rate
(measured from T0+8.192 to T0+8.960 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.35(-0.14,+0.15),
the high energy photon index beta = -4.34(-5.66,+0.70),
the peak energy Ep = 117(-5,+5) keV
(chi2 = 31/46 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181227_T22619/

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


GRB_name: GRB181228A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23590
SUBJECT: GRB 181228A: MITSuME Akeno optical upper limits
DATE:    18/12/30 12:22:33 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

M. Oeda, K. L. Murata, R. Itoh, Y. Tachibana, S. Harita, K. Morita, K.
Shiraishi, K. Iida, M. Niwano, R. Adachi, Y. Yatsu, and N. Kawai (Tokyo
Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 181228A (M. J. Moss  et al.,
GCN Circular #23570) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Akeno Observatory,
Yamanashi, Japan.

The observation started on 09:04:35.19 UT. We did not find any new point
source within the enhanced XRT circle (A.P. Beardmore et al., GCN Circular
#23574) in all three bands. We obtained following limits for the magnitudes.

T0+[hour]    MID-UT      T-EXP[sec]    g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
6.188       13:04:51          25320      >19.1     >19.0     >18.6
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.


GRB_name: GRB181227A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23591
SUBJECT: GRB 181227A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/12/30 13:26:47 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

S. Sugita, A. Yoshida, T. Sakamoto, V. Pal'shin (AGU), Y. Kawakubo (LSU),
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long soft GRB 181227A (Fermi GBM detection: Bissaldi & Veres,
GCN Circ. 23569; IPN Triangulation: Hurley et al., GCN Circ. 23577;
Konus-Wind observation: Svinkin et al., GCN Circ. 23589)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 06:17:09.332 UTC
on 27 December 2018.
Because of a problem in one of the ground alert processing scripts,
the GCN notice was not distributed automatically for this event.

Since the burst incident direction was at ~110 deg relative
to the detector's axes, the signal is barely seen in the HXM detectors,
and it was heavily attenuated in the SGM detector.

The burst light curve shows a single emission episode which starts
at T-9.0 sec and ends at T+7.1 sec.
The T90 and the T50 durations measured by the SGM data are
13.9 +- 2.4 sec and 5.9 +- 2.3 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1229926558/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.


GRB_name: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23593
SUBJECT: GRB 181228A: possible NOT optical detection
DATE:    18/12/31 00:02:45 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu (NAOC), D.B. Malesani (DAWN/NBI/DTU and DARK/NBI), J.P.U. Fynbo 
(DAWN/NBI and DAWN/DTU), M.I. Andersen (NBI), T. Pursimo (NOT) report:

We observed the field of GRB 181228A (Moss et al., GCN 23570) using the 
2.56m Nordic Optical Telescope (NOT) equipped with ALFOSC, starting at 
23:56:20 UT on 2018-12-28, i.e., 21.05 hr after the BAT trigger. We 
obtained 3x300s unfiltered frames and 3x300s frames in the Sloan i-band.

There is a weak detection in our stacked image at the REM position 
(D'Avanzo et al., GCN 23575), thus also being consistent with the 
enhanced XRT error circle (Beardmore et al., GCN 23574). The above 
position is not consistent with that of MASTER OT reported in Lipunov et 
al. (GCN 23576). The NOT source has m(i)~25.0+/-0.5, calibrated with 
nearby PanSTARRS stars, and thus it could be the optical counterpart of 
GRB 181228A.


GRB_name: GRB181228A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23594
SUBJECT: GRB 181228A: Global MASTER Net  OT is the same REM IR transient 
DATE:    18/12/31 09:57:40 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, N.Tiurina, E. Gorbovskoy, V.Kornilov,  P.Balanutsa,
A.Kuznetsov, D. Vlasenko, D.Kobtsev
(Lomonosov Moscow State University, SAI),

R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix 
Aguilar),

H. Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio of San Juan 
National University, Argentina)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
(The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

A. Tlatov, V.Senik,  D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

O. Gress, N.M. Budnev, S. Yazev, O. Chuvalaev (Irkutsk State University, API)

V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State 
University)



The optical source detected by MASTER (Lipunov et al., GCN 23576) insidet 
Swift BAT GRB 181228A error box (Moss et al., GCN 23570) 
regardless of the infrared telescope REM  (D'Avanzo et al., GCN 23575)
is one and the same source. The difference in coordinates is less than 3 
sigma. Our coordinates are of course rather rough, since the source itself 
is very weak. Let me remind you that the pixel MASTER is equal to 2.5 
arcsec.
OT (not infrared)  discovered by MASTER is disappear on late imeges!

HNY!

The message may be cited.


GRB_name: GRB181225A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23595
SUBJECT: GRB 181225A: further Swift-XRT observations
DATE:    18/12/31 15:02:44 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

V. D Elia (SSDC) reports on behalf of the Swift-XRT team:

Swift-XRT has performed a second follow-up observation of the AGILE-, GBM- and LAT-detected burst GRB 181225A (Ursi et al., GCN Circ. 23560; Arimoto et al. GCN Circ., 23561; Poolakkil et al., GCN Circ. 23562). The XRT total exposure time is 7 ks. The data were collected 5.6 days after the trigger, and are entirely in Photon Counting (PC) mode.

The two sources detected in the first XRT observation (Dâ€™Elia et al., GCN Circ 23565) are still present in the XRT field of view of the new observation, with consistent rates and positions. We thus conclude that they are unrelated to the X-ray afterglow of GRB181225A. 

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


GRB_name: GRB181228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23596
SUBJECT: GRB 181228A: Mondy and AbAO optical upper limits
DATE:    18/12/31 17:37:10 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), R. Ya. Inasaridze 
(AbAO),  E. Mazaeva (IKI),   A. Volnova (IKI), V. R. Ayvazian (AbAO), 
G. V.  Kapanadze (AbAO)   report   on behalf of the IKI GRB-FuN:

We observed the field of GRB 181228A (Moss et al., GCN 23570; Beardmore 
et al., GCN 23574) with AZT-33IK telescope of Sayan observatory (Mondy) 
   starting on Dec. 28 (UT) 13:48:11 in I-filter, and AS-32 telescope of 
Abastumani Observatory (AbAO) on Dec. 28 (UT) 15:13:46 in R-filter. We 
do not detected    the afterglow (D'Avanzo et al., GCN 23575; Lipunov et 
al. GCN 23576; Xu et al., GCN 23593).

Preliminary photometry of the field  is following.

Date       UT start t-T0    Filter Exp.  OT    Err. UL
                    (mid, days) (s)

2018-12-28 13:48:11 0.47494 I      30*120 n/d  n/d   23.8
2018-12-28 15:13:46 0.54879 R      63*60  n/d  n/d   21.0


The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2    I2
1032-0046066 16.66 16.08
1031-0043284 16.04 15.36


GRB_name: GRB181231A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23597
SUBJECT: GRB 181231A: Fermi-LAT detection
DATE:    18/12/31 17:55:29 GMT
FROM:    Masanori Ohno at Hiroshima University  <ohno@astro.hiroshima-u.ac.jp>

F. Dirirsa (U. Johannesburg) and M. Ohno (Hiroshima U.)
report on behalf of the Fermi-LAT team:

On December, 31, 2018 Fermi-LAT detected high-energy emission from GRB
181231A, which was also detected by Fermi-GBM (trigger 567919668 /
181231144).

The best LAT on-ground location is found to be

RA, Dec = 254.59, 0.61 (degrees, J2000)

with an error radius of 0.24 deg (90 % containment, statistical error
only).
This was 51 deg from the LAT boresight at the time of the GBM trigger:

T0 =  03:27:43.8 UT.

The data from the Fermi-LAT show a significant increase
in the event rate after the GBM trigger that is spatially correlated with
the
GBM emission (7.8 degrees from the GBM location) with high significance.
The photon flux above 100 MeV in the time interval 0-5000 s after the
GBM trigger is 2.4 (+/-1.2)E-6 ph/cm2/s.
The estimated photon index above 100 MeV is 2.21 (+/-0.37).

A Swift ToO has been requested for this burst

The Fermi-LAT point of contact for this burst is Feraol F. Dirirsa (
fdirirsa@uj.ac.za).

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: GRB181231A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23598
SUBJECT: GRB 181231A: Fermi GBM detection
DATE:    18/12/31 18:56:12 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres, R. Hamburg and C. Meegan (all UAH)
report on behalf of the Fermi GBM Team:

"At 03:27:43.75 UT on 31 December 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181231A (trigger 567919668 / 181231144)
which was also detected by Fermi/LAT (Dirirsa et al., GCN 23597).
The GBM on-ground location is consistent with the LAT position.

The GBM light curve shows multiple peaks
with a duration (T90) of about 37 s (50-300 keV).
The time-averaged spectrum from T0-7.2 s to T0+30.7 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.63 +/- 0.13 and
the cutoff energy, parameterized as Epeak, is 215 +/- 25 keV.

The event fluence (10-1000 keV) in this time interval is
(6.23 +/- 0.46)E-6 erg/cm^2. The 1 second peak photon flux measured
starting from T0+14.3 s in the 10-1000 keV band
is 2.70 +/- 0.27 ph/s/cm^2.


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


GRB_name: GRB181231A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23599
SUBJECT: GRB 181231A: BOOTES-2/TELMA optical observations
DATE:    19/01/01 12:28:58 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado 
(IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de 
Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC), M.D. Caballero-Garcia and 
M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:

The 60cm BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) 
in Algarrobo Costa (Malaga, Spain) followed up GRB 181231A (Veres et al 
GCNC 23598). Nine images (60s exposure, unfiltered) were obtained with 
the COLORES imager spectrograph starting at 05:35:26 UT (~26.1 hr after 
trigger) in order to cover the entire Fermi/LAT error box (Dirirsa et 
al. GCNC 23597). No new optical sources were detected down to 18 mag.

This message can be quoted.


GRB_name: GRB190103A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23600
SUBJECT: GRB 190103A: AGILE/MCAL detection of a burst
DATE:    19/01/03 20:28:34 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

A.Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A.
Argan, M. Cardillo, C. Casentini, Y. Evangelista, G. Piano (INAF/IAPS), F.
Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli,
V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi
(INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN
Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team:

The AGILE Mini-CALorimeter (MCAL) detected a burst at T0 = 2019-01-03
16:42:15.05 +/- 0.01 s (UTC).

The event lasted about 4.7 s and released a total number of ~5426 counts in
the detector (in the 0.4-100 MeV energy range), above an average background
rate of about 700 Hz. The light curve shows two peak episodes.

The GRB is clearly detected also by the AGILE scientific ratemeters; in
particular, by the Super-AGILE (20-60 keV), Anti-Coincidence (50-200 keV),
and MCAL (0.4-100 MeV) ratemeters.

Further analysis is still in progress.

The AGILE-MCAL detector has a full solid angle acceptance, and is
operational in the range 0.4 - 100 MeV.


GRB_name: GRB181201A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23601
SUBJECT: GRB 181201A: photometric signature of the SN
DATE:    19/01/03 20:40:28 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), E. Mazaeva (IKI),  A. Pozanenko (IKI),  P. Minaev 
(IKI), A. Volnova (IKI), N. Tominaga (Konan University), S. Blinnikov 
(ITEP), D. Chestnov (KIAM), E. Klunko (ISTP), I. Reva (FAPI), V. 
Rumyantsev (CrAO),  D. Buckley (SAAO), R. Ya. Inasaridze (AbAO) report 
on behalf of  GRB-FuN collaboration:

We observed  the   optical afterglow (e.g. Podesta et al., GCN  23470; 
Kong  GCN 23475) of the INTEGRAL GRB 181201A  (Mereghetti et al., GCN 
23469)  with   Gemini-N telescope  on Dec. 22 in g'r'i'z and Dec. 24  in 
r'i'-filters.  Preliminary photometry of the OT is following.

Date            t-T0  Filter Exp.   OT     Err.
                 (mid, days)  (s)

2018-12-22  21.10536 i'     3*180  21.50  0.03
2018-12-22  21.09536 r'     3*180  21.82  0.03
2018-12-24  23.09418 i'     3*180  21.32  0.06
2018-12-24  23.10793 r'     3*240  21.83  0.03

The photometry is based on the SDSS-DR12 star
SDSS-DR12_id           i' r'
J211710.81-123706.3    16.257 16.517

Based on our previous observations and photometry reported in GCNs 
23475, 23478,  23486, 23504 we plot a light curve of the afterglow in 
r'-filter (http://grb.rssi.ru/GRB181201A/GRB181201A_optics_fit.png). 
Power law approximation of the LC before 2018-12-22 has an index of 
1.19 +/-0.01. The photometry obtained on 2018-12-22 and 2018-12-24 has a 
significance of about 2 and 6.5 sigma above the power law approximation. 
Additionally the i'-magnitude increases between  the two epochs. We can 
suggest that we observed the Supernova signature associated with GRB 
181201A.


GRB_name: GRB190103B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23602
SUBJECT: GRB 190103B: Swift detection of a burst
DATE:    19/01/03 21:14:34 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. A. Kennea (PSU),
H. A. Krimm (NSF/USRA), M. J. Moss (George Washington University),
K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC) and A. Tohuvavohu (PSU) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 21:03:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190103B (trigger=881709).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 212.574, +35.261, which is 
   RA(J2000)  =  14h 10m 18s
   Dec(J2000) = +35d 15' 40"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several overlapping peaks
with a duration of about 40 sec.  The peak count rate
was ~5800 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 21:05:24.5 UT, 93.3 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 212.5695, 35.2617 which is equivalent to:
   RA(J2000)  = 14h 10m 16.68s
   Dec(J2000) = +35d 15' 42.1"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 13 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 7.42e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 102 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 A. Y. Lien (amy.y.lien 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: GRB190103B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23603
SUBJECT: GRB 190103B: Enhanced Swift-XRT position
DATE:    19/01/04 01:34:44 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2781 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 190103B, 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 = 212.56927, +35.26100 which is equivalent
to:

RA (J2000): 14h 10m 16.63s
Dec (J2000): +35d 15' 39.6"

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: GRB190103B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23604
SUBJECT: GRB 190103B: Swift-XRT refined Analysis
DATE:    19/01/04 04:24:42 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page
(U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB),
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), A.
Tohuvavohu (PSU) and A.Y. Lien report on behalf of the Swift-XRT team:

We have analysed 7.8 ks of XRT data for GRB 190103B (Lien et al. GCN
Circ. 23602), from 99 s to 18.1 ks after the  BAT trigger. The data
comprise 437 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Evans et al. (GCN Circ. 23603).

The late-time light curve (from T0+4.2 ks) can be modelled with a
power-law decay with a decay index of alpha=1.03 (+/-0.10).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.38 (+/-0.06). The
best-fitting absorption column is  4.27 (+0.28, -0.27) x 10^21 cm^-2,
in excess of the Galactic value of 1.4 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.89 (+/-0.11) and a
best-fitting absorption column of 3.9 (+0.6, -0.5) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.1 x 10^-11 (6.0 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.9 (+0.6, -0.5) x 10^21 cm^-2
Galactic foreground: 1.4 x 10^20 cm^-2
Excess significance: 11.8 sigma
Photon index:      1.89 (+/-0.11)

If the light curve continues to decay with a power-law decay index of
1.03, the count rate at T+24 hours will be 0.027 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (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/00881709.

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


GRB_name: GRB190103B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23606
SUBJECT: GRB 190103B: Swift-BAT refined analysis
DATE:    19/01/04 16:24:28 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 190103B (trigger #881709)
(Lien, et al., GCN Circ. 23602).  The BAT ground-calculated position is
RA, Dec = 212.561, 35.254 deg which is
  RA(J2000)  =  14h 10m 14.6s
  Dec(J2000) = +35d 15' 13.4"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 6%.

The mask-weighted light curve shows several overlapping pulses that starts at
~T-10 s and ends at ~T+16 s. The main peak occurs at ~T0. T90 (15-350 keV)
is 19.5 +- 2.7 sec (estimated error including systematics).

The time-averaged spectrum from T-10.43 to T+16.18 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.99 +- 0.29,
and Epeak of 85.0 +- 18.6 keV (chi squared 58.41 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+0.60 sec in the 15-150 keV band is
16.3 +- 1.5 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.63 +- 0.06 (chi squared 74.91 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/881709/BA/


GRB_name: GRB190103B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23607
SUBJECT: GRB 190103B: Bassano Bresciano observatory upper limit 
DATE:    19/01/04 17:41:11 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Obs  <oabb@ulisse.bs.it>

U.Quadri, L.Strabla and A.Quadri report:

We imaged the field of GRB 190103B detected by SWIFT(trigger 881709)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
ISSP - Italian Supernovae Search Project.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.

The observations started 194.16 min after the GRB trigger,  
with our Schmidt telescope D=320/400 mm F/D=3.1.

Weather conditions were good.

We co-added 64 exposures of 240 sec each.

Start T0+      End T0+       Vlim
194.16 min   459.27 min    19.5

We did not found any optical counterpart in the error box of the XRTcandidate.
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. A. Kennea (PSU), et al.

Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.

Reference:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.


GRB_name: GRB190103A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23609
SUBJECT: GRB 190103A: AstroSat CZTI detection
DATE:    19/01/05 11:44:14 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

T. Khanam, V. Sharma and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), D. Bhattacharya (IUCAA), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 190103A, which was also detected by AGILE/MCAL (Ursi A. et al., GCN 23600).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 16:42:16.500 UT, ~ 1 s after AGILE/MCAL trigger. The measured peak count rate is 2221 cts/s above the background in combined data of four quadrants, with a total of 10698 cts. The local mean background count rate was 486.7 cts/s. Using cumulative rates, we measure a T90 of 25.4 s. In preliminary analysis, we find that 927 compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190103B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23612
SUBJECT: Konus-Wind observation of GRB 190103B
DATE:    19/01/05 19:47:56 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The  GRB 190103B (Swift detection: Lien et al., GCN 23602;
Markwardt  et al., GCN 23606)
triggered Konus-Wind at T0=75832.010 s UT (21:03:52.010).

The burst light curve shows a double-peaked structure
which starts at ~T0-10 s and has a total duration of ~27 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.96(-0.08,+0.08)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+1.408 s,
of 3.87(-0.79,+0.79)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+22.528 s)
is best fit in the 20 keV - 16 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.17(-0.09,+0.09),
and Ep = 142(-9,+11) keV (chi2 = 97/98 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.88 (chi2 = 97/97 dof).

The spectrum near the peak count rate
(measured from T0+0.256 to T0+6.144 s)
is best fit in the 20 keV - 16 MeV range
by the power law with exponential cutoff model
with  alpha = -0.96(-0.10,+0.10),
and Ep = 157(-10,+11) keV (chi2 = 90/92 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.92 (chi2 = 90/91 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190103_T75832/

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


GRB_name: GRB190106A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23615
SUBJECT: GRB 190106A: Swift detection of a burst with an optical counterpart
DATE:    19/01/06 13:45:24 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU), C. Gronwall (PSU),
N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC) and
K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 13:34:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190106A (trigger=882252).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 29.886, +23.857, which is 
   RA(J2000)  =  01h 59m 33s
   Dec(J2000) = +23d 51' 24"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows multiple peaks
with a duration of about 100 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~10 sec after the trigger. 

The XRT began observing the field at 13:36:06.3 UT, 81.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 29.87964, 23.84516 which
is equivalent to:
   RA(J2000)  = 01h 59m 31.11s
   Dec(J2000) = +23d 50' 42.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 47 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 0.1 s image was 1.98e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 90 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 01:59:31.18 =  29.87993
  DEC(J2000) = +23:50:44.0  =  23.84555
with a 90%-confidence error radius of about 0.61 arc sec. This position is 5.0
arc sec. from the center of the XRT error circle. The estimated magnitude is
16.45 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.09. 

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


GRB_name: GRB190106A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23616
SUBJECT: GRB 190106A: MASTER Amur OT detection
DATE:    19/01/06 14:20:15 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, A.Kuznetsov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, 
N.Tyurina,  P.Balanutsa,D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University


V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev
Blagoveschensk Educational State University, Blagoveschensk

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

K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory

MASTER-Amur robotic telescope (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical 
University) was pointed to the  GRB190106.57 (Swift BAT alert, GCN 23615) 
20 sec after notice time and 
36 sec after trigger time at 2019-01-06 13:35:20 UT. On our first (10s 
exposure)  set we found optical transient  within SWIFT BAT error-box 
(ra=29.8792 dec=23.8567 r=0.05).
The 5-sigma upper limit has been about 16.5mag

RA, DEC = 01h 59m 31.20s +23d 50m 44.04s
mag = 16.0
The automatical photometry are:

start time      coord2000    Band  mag emag  exp

13:35:20.0   1h 59m 31.17s +23d 50m 44.5s   P   16.2    0.20   10
13:35:46.6   1h 59m 31.19s +23d 50m 44.8s   P 15.2 0.14   10
13:36:12.6   1h 59m 31.23s +23d 50m 44.1s   P 15.8 0.15   20
13:36:47.8   1h 59m 31.19s +23d 50m 44.6s   P 16.2 0.17   20
13:37:24.9   1h 59m 31.23s +23d 50m 44.5s   P 15.8 0.11   30
13:38:08.7   1h 59m 31.18s +23d 50m 44.2s   P 15.4 0.08   40 
13:39:03.1   1h 59m 31.17s +23d 50m 44.2s   P 15.7 0.07   50
13:40:07.0   1h 59m 31.18s +23d 50m 44.1s   P 15.5 0.09   60
13:41:35.5   1h 59m 31.20s +23d 50m 44.0s   P 15.6 0.10   60
13:43:03.7   1h 59m 31.18s +23d 50m 44.3s   P 15.9 0.11   60
13:44:28.9   1h 59m 31.18s +23d 50m 43.8s   P 16.1 0.12   60
...............................
to be continuated...


This optical counterpart is coincident with Swift optical object (Sonbas 
et al., GCN 23615).

The galactic latitude b = -36 deg., longitude l = 143 deg.
The observations made on zenit distance = 45 deg.The moon ( 0 % bright 
part) below the horizon (The altitude of the Moon is -50 deg. ).
The sun  altitude  is -53.7 deg.
The object can be observed till 2019-01-07 18:34:53

This message may be cited, but this is the first automatic photometry.
Non monotonic light curve was detected.


GRB_name: GRB190106A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23617
SUBJECT: GRB 190106A: MITSuME Akeno optical observation
DATE:    19/01/06 14:36:58 GMT
FROM:    Ryosuke Itoh at Tokyo Institute of Tech.  <itoh@hp.phys.titech.ac.jp>

R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita,
K. Shiraishi, K. Iida, M. Niwano, R. Adachi, M. Oeda,  Y. Yatsu,
and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration

We searched for the optical counterpart of GRB 190106A (Sonbas et al., GCN
Circular #23615) with the optical three color (g', Rc, and Ic) CCD cameras
attached to the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 13:35:33 UT which corresponds to
49 sec after the trigger.
We detected the point source at the position consistent with the Swift/UVOT
observation (Sonbas et al., GCN Circular #23615) and MASTER
observation (Lipunov et al., GCN Circular #23616).
The measured magnitudes are listed as follows.

T0+[sec]    MID-UT      T-EXP[sec]        g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
~49      13:36:02.6           60               ~16.1      ~15.6   ~15.5
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.
The magnitudes are expressed in the AB system.

Further analysis is ongoing.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23618
SUBJECT: GRB 190106A: GMG detection
DATE:    19/01/06 14:40:05 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao_obs@ynao.ac.cn>

J. Mao, Y.-X. Xin, Y. Li, and J.-M. Bai (YNAO) report:


We observed the field of GRB 190106A (Sonbas et al., GCN 23615) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. Observations began about 0.5 hours after the trigger. We clearlydetected the optical source reported by Yurkov et al. (GCN 23614). The spectral observation is ongoing.  


GRB_name: GRB190106A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23619
SUBJECT: GRB 190106A: Enhanced Swift-XRT position
DATE:    19/01/06 15:22:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 621 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 190106A, 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 = 29.88004, +23.84544 which is equivalent
to:

RA (J2000): 01h 59m 31.21s
Dec (J2000): +23d 50' 43.6"

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: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23620
SUBJECT: GRB 190106A : TSHAO optical observations
DATE:    19/01/06 15:27:05 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

I. Reva (FAPHI), A. Pozanenko (IKI),
  A. Kusakin (FAPHI), S. Belkin (IKI), A. Volnova (IKI),  E. Mazaeva 
(IKI), M. Krugov (FAPHI) report on behalf of larger GRB follow-up 
collaboration:

We observed the optical transient (Yurkov et al., GCN 23614; Sonbas et 
al., GCN 23615; Lipunov et al., GCN 23616; Itoh et al., GCN 23617) of 
GRB 190106A (Sonbas et al., GCN 23615) with Zeiss-1000 1-m telescope of 
Tien Shan Astronomical Observatory starting on Jan. 6 (UT) 13:45:42. 
Preliminary photometry of the object in the beginnig of observations is 
R= 16.23 +/- 0.05, and the optical transient is faded as R= 17/5 +/- 0.1 
at (UT) 14:24:04. (The photometry is based on nearby USNO-B1.0 stars). 
Observations are continuing in R and B - filters.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23622
SUBJECT: GRB 190106A: GWAC-F60B optical detection 
DATE:    19/01/06 15:40:35 GMT
FROM:    L.P. Xin at NAOC  <xlp@nao.cas.cn>

L. P. Xin,  P. P. Zhang, R. S. Zhang,  J. Wang,   J. Y. Wei,   E. W. Liang, 
X. G. Wang, Y. J. Xiao,   Y. G. Yang,  X. M. Lu,  L. Huang,    H. B. Cai,   
Y. L. Qiu,  Y. Xu, Y.  J. Xiao, Y. T. Zheng,  C. Wu,   J. S. Deng,  D. W. Xu, 
D. TURPIN, H. L. Li, and W. L. Dong, report:

We  observed  GRB 190106A  ( Sonbas et al., GCN 23615 )  
with  GWAC-F60B 60cm optical telescope  at 14:51:03 UT, 
Jan. 06th 2019,  about 77  min after the burst. 

The optical afterglow reported by ( Sonboas et al., GCN 23615; 
Lipunov et al., GCN 23636; Itoh et al., GCN23617; Mao et al., GCN 23618 )
is clearly detected  in R band images. The brightness is 17.8mag 
calibrated by nearby USNO-B1.0 stars.

GWAC-F60B is operated by Guangxi university and NAOC, CAS, 
at Xinglong observatory, China.

Further observation is continuing. 

The message may be cited.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23623
SUBJECT: GRB 190106A: Xinglong-2.16m spectroscopy
DATE:    19/01/06 17:23:09 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

Z.P. Zhu, D. Xu, Y. Wang, J.B. Zhang (NAOC), J.H. Liu, X. Zhang (XAO) 
report:

We observed the optical afterglow of GRB 190106A (Sonbas et al., GCN 
23615) using the Xinglong-2.16m telescope equipped with BFOSC. We 
acquired 1x3600 s and then 1x2400 s spectra starting at 14:02:39 UT on 
2019-01-06, i.e., 27.9 mins after the burst. The optical afterglow was 
R~16 mag at this time.

 From preliminary analysis, a continuum is detected across the spectral 
range of 3600 - 9000 AA. A few absorption features are also detected due 
to Fe II, Al II, Mn II, Mg II doublet, and Mg I, at a redshift of 
z~0.896, which we propose as the likely redshift of the GRB.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23624
SUBJECT: GRB 190106A: Bassano Bresciano Observatory optical detection
DATE:    19/01/06 20:57:28 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Obs  <oabb@ulisse.bs.it>

U.Quadri, L.Strabla and A.Quadri report:

We imaged the field of GRB 190106A detected by SWIFT(trigger 882252)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
ISSP - Italian Supernovae Search Project.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.

The observations started 6.16 hour after the GRB trigger,  
with our baker-Schmidt telescope D=250 mm F/D=3.

Weather conditions were good.

We co-added 2 series of 15 exposures of 60 sec each.

Start T0+      End T0+      Vlim
6.16 hour   6.72 hour       19.5

We detect the afterglow in the error box of the XRTcandidate.
E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC), et al.
at the following position (+/- 2 arcsec):

RA (J2000) =  01h 59m 31.50s
DEC(J2000) = +23Â° 50' 44.7"

The results of our photometry are:

------------------------------------    
     JD          V mag       Cat
------------------------------------
2458490.33004   19.130 V    UCAC4   
2458490.34077   19.344 V    UCAC4   
------------------------------------
 
Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.

The images are available at:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.


GRB_name: GRB190106A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23625
SUBJECT: GRB 190106A: Swift-BAT refined analysis
DATE:    19/01/06 21:07:30 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.), M. Stamatikos (OSU),
T. N. Ukwatta (LANL)  (i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+695 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 190106A (trigger #882252)
(Sonbas, et al., GCN Circ. 23615).  The BAT ground-calculated position is
RA, Dec = 29.877, 23.839 deg, which is 
   RA(J2000)  =  01h 59m 30.6s 
   Dec(J2000) = +23d 50' 20.8" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 65%.
 
The mask-weighted light curve shows it started at ~T-10sec, with a pair of
overlapping FRED-like peaks at ~T+2 and ~T+10 sec, then a long decay and
two more peaks at ~T+57 and ~T+76 sec, and returning to baseline
at ~T+125 sec.  T90 (15-350 keV) is 76.8 +- 2.4 sec (estimated error
including systematics).
 
The time-averaged spectrum from T-0.17 to T+99.72 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.34 +- 0.21, 
and Epeak of 120 +- 83 keV (chi squared 37.25 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 6.0 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+75.28 sec in the 15-150 keV band is
5.5 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.64 +- 0.05 (chi squared 43.44 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/882252/BA/


GRB_name: GRB190106A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23626
SUBJECT: GRB 190106A: Swift/UVOT Detection
DATE:    19/01/06 21:43:23 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190106A
90 s after the BAT trigger (Sonbas et al., GCN Circ. 23615).
A source consistent with the XRT position (Goad et al. GCN Circ. 23619)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  01:59:31.16 =  29.87985 (deg.)
    Dec (J2000) = +23:50:43.9  =  23.84552 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).

The source was also detected by MASTER (Yurkov et al, GCN Circ.
23614,23616),
MITSuME (Itoh et al, GCN Circ. 23617), GMG (Mao et al, GCN Circ. 23618),
TSHAO (Reva et al, GCN Circ. 23620), GWAC-F60B (Xin et al, GCN Circ. 23622),
Xinglong (Zhu et al, GCN Circ. 23623) who report a redshift of z~0.896 and
Bassano Bresciano Observatory (Quadri et al, GCN Circ. 23624).

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are:

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

white               90          240          147         16.64 +/- 0.03
v                  633          653           20         16.54 +/- 0.16
b                  559          579           20         16.70 +/- 0.09
u                  304          553          246         15.97 +/- 0.03
w1                 682          702           20         17.36 +/- 0.29

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23627
SUBJECT: GRB 190106A: BOOTES-4/MET optical observations
DATE:    19/01/06 22:39:38 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado 
(IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de 
Malaga), S. Guziy (Nikolaev Astronomical Observatory) and D. Xiong, Y. 
Fan, X. Zhao, J. Bai, C. Wang, Y. Xin (Yunnan Nacional Astronomical 
Observatory) on behalf of a larger collaboration, report:

Following the detection of GRB 190106A by Swift (Sonbas et al. GCNC 
23615), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical 
Observatory (China) triggered alert at 15:12:56 UT (~1.6 hr after 
trigger). The reported optical afterglow (Yurkov et al. GCNC 23614, 
Lipunov et al. GCNC 23616, Itoh et al. GCNC 23617, Mao et al. GCNC 
23618, Reva et al. GCNC 23620 and Xin et al. 23622) is still clearly 
detected within the refined XRT position (Goad et al. GCNC 23619). A 
preliminary photometry yields a magnitude of 19.4 +/- 0.1 (g-band). 
Observations are ongoing.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23628
SUBJECT: GRB 190106A: OASDG optical observations
DATE:    19/01/06 23:33:26 GMT
FROM:    Luca Izzo at IAA-CSIC  <luca.izzo@gmail.com>

A. Noschese (AC-OASDG), L. Izzo (IAA-CSIC), A. Di Dato and L. Dâ€™Avino (AC-OASDG) report:

We observed the field of GRB 190106A (Sonbas et al. GCN 23615) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( https://goo.gl/Dqvqhf ). 

We obtained a series of 3x180 s images in the Rc filter, starting at 21:44:38 UT, ~ 8.17 hrs after the GRB detection. In our stacked image, we find a source at the position of the observed optical counterpart (Lipunov  et al. GCN 23616, Itoh et al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 23620, Xin et al. GCN 23622, Quadri et al. GCN 23624, Hu et al. GCN 23627) for which we measure a magnitude of Rc(AB) = 19.47 +/- 0.10 mag. The calibration was performed using nearby stars in the USNO B1 catalog.


GRB_name: GRB190106A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23629
SUBJECT: GRB 190106A: update of the Xinglong-2.16m spectroscopy
DATE:    19/01/07 05:25:15 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu, Z.P. Zhu, Y. Wang, J.B. Zhang (NAOC), J.H. Liu, X. Zhang (XAO) 
report:

We have re-reduced the 3600s+3000s spectra taken from the Xinglong-2.16m 
telescope (Zhu et al., GCN 23623), with the calibration frames taken in 
the same night. The Signal-to-Noise of the spectrum increased compared 
with the previous 3600s one, and the resolution is not high due to 
seeing~2.0".

We only consider relatively prominent absorption features and thus only 
six features are left, which can be interpreted as C IV 1547.62, 1550.19,
Fe II 2585.88, 2599.40, and Mg II doublet 2795.53, 2802.71
(wavelength in air), at an updated and consistent redshift of z=1.86.

[GCN OPS NOTE(08jan19): Per author's request, In the SUBJECT-line,
the "180106A" was changed to "190106A".  And the
"Fe II 1547.62, 1550.19, 2585.88, 2599.40, and Mg II doublet 2795.53, 2802.71" was changed to
"C IV 1547.62, 1550.19, Fe II 2585.88, 2599.40, and Mg II doublet 2795.53, 2802.71".]


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23630
SUBJECT: GRB 190106A: GMG spectral results
DATE:    19/01/07 10:41:54 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao_obs@ynao.ac.cn>

J. Mao, Y.-X. Xin, Y. Li, J.-M. Bai (YNAO), J. Wang, and L. P. Xin (NAOC) report:


We observed the afterglow of GRB 190106A with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. The spectral observations began about 0.5 hours after the trigger. The spectrum has excellent S/N. Some absorption lines, such as SiIV 1394, SiII 1527, AlII 1671, AlIII 1855/1863, CrII+ZnII 2062, and FeII 2344/2383, were clearly detected. This indicates a redshift of about 1.86, consistent with the result of Xu et al. (GCN. 23629). Moreover, we note a possible broad emission feature around 4500A, and further analysis is ongoing.      


GRB_name: GRB190103B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23631
SUBJECT: GRB 190103B: CALET Gamma-Ray Burst Monitor detection
DATE:    19/01/07 11:40:49 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

A. Tezuka, A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone 
(AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 190103B (Swift-BAT trigger #881709: Lien et al.,
GCN Circ. 23602, Markwardt et al., GCN Circ. 23606;
Konus-Wind observation: Tsvetkova et al., GCN Circ. 23612)
triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 21:03:46.478 UTC on 3 January 2019.
The burst signal was seen by all CGBM detectors.

The burst light curve shows two multi-peaked pulses which
start at T-6.9 sec, peak at T+5.4 sec, and end at T+22.3 sec.
The T90 and the T50 durations measured by the SGM data are
19.6 +- 2.5 sec and 9.1 +- 1.0 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1230584543/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23632
SUBJECT: GRB 190106A: VLT/X-shooter redshift confirmation
DATE:    19/01/07 13:01:48 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

P. Schady (Univ. of Bath), D. Xu (NAOC), K. E. Heintz (Univ. of Iceland), N. R. Tanvir (Univ. Leicester), D. B. Malesani (DAWN/NBI and DARK/NBI), D. A. Kann (HETH/IAA-CSIC), R. Sanchez-Ramirez (INAF/IAPS) and K. Wiersema (Univ. of Warwick) report:

We observed the optical counterpart of GRB 190106A (Sonbas et al., GCN #23615; Yurkov et al., GCN #23614) with the ESO-VLT UT2 (Kueyen) equipped with the X-shooter spectrograph, covering the wavelength range 3000-21000 AA. We acquired four 600 second spectra on 2019-01-07 between 00:53UT and 01:47UT, approximately 11 hours after the GRB. In the acquisition image we measure r = 19.47 +/- 0.02 (AB), calibrated against a nearby Pan-STARRS object.

We detect several absorption features at a common redshift z = 1.859, consistent with the value reported by Xu et al. (GCN #23629) and Mao et al. (GCN #23630). In addition to the absorption lines reported by Xu et al. and Mao et al., we also detect O I, C II, Mg I, and C IV, all at the same redshift, as well a broad feature due to H I Lyalpha absorption.

We acknowledge Steffen Mieske and Joe Anderson at Paranal for their excellent help in obtaining these observations. 


GRB_name: GRB190106A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23633
SUBJECT: GRB 190106A: Swift-XRT refined Analysis
DATE:    19/01/07 13:45:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte
(PSU) and V. Yurkov report on behalf of the Swift-XRT team: report on
behalf of the Swift-XRT team:

We have analysed 5.7 ks of XRT data for GRB 190106A (Yurkov et al. GCN
Circ. 23614), from 85 s to 44.7 ks after the  BAT trigger. The data
comprise 254 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN Circ. 23619).

The late-time light curve (from T0+11.7 ks) can be modelled with a
power-law decay with a decay index of alpha=1.02 (+/-0.11).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.06 (+0.06, -0.05). The
best-fitting absorption column is  1.9 (+/-1.1) x 10^21 cm^-2, at a
redshift of 1.86, in addition to the Galactic value of 1.0 x 10^21
cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index
of 1.95 (+0.09, -0.06) and a best-fitting absorption column consistent
with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum  is 3.5 x 10^-11 (4.4
x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Galactic foreground: 1.0 x 10^21 cm^-2
Intrinsic column:    1.0 (+1.6, -0.0) x 10^21 cm^-2 at z=1.86
Photon index:      1.95 (+0.09, -0.06)

If the light curve continues to decay with a power-law decay index of
1.02, the count rate at T+24 hours will be 0.096 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.4 x
10^-12 (4.2 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/00882252.

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


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23634
SUBJECT: GRB 190106A: GMG photometry in the 2nd night
DATE:    19/01/07 14:15:26 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao_obs@ynao.ac.cn>

J. Mao, Y.-X. Xin, Y. Li, J.-M. Bai (YNAO) report:


We observed the afterglow of GRB 190106A with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories in the second night. The observation began at UT 12:47:01, 7th, Jan, 2019, about 23.2 hours after the trigger. We still clearly detected the source. A preliminary measurement provided a magnitude of R~19.7. We suggest other telescopes to keep on observations.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23635
SUBJECT: IERCOO/ICSP optical observation of GRB 190106A
DATE:    19/01/07 16:12:16 GMT
FROM:    Sandip K. Chakrabarti at ICSP  <sandipchakrabarti9@gmail.com>

IERCOO/ICSP  optical observation of GRB 190106A


Sandip K. Chakrabarti, Argha Sil, Shyam Sarkar, Ashim Sarkar, D.
Bhowmick (Indian
Centre for Space Physics)
We observed GRB 190106A using 0.61m reflector of our observatory at
Sitapur, West Bengal, India. The observation was with R, V, and B filters
in a short interval at around 16:45UT on 6th January, 2019, i.e., about
three hours after the BAT trigger (Sonbas et al. 2019; GCN 23615). Using
two exposures each of 90s in R and in V, we obtained the magnitudes of
17.83+/-0.25 and 18.45 +/- 0.23 respectively. Using one 90s exposure in B,
we obtained the magnitude of 18.81+/-0.39. Using triangulation, we obtained
the location of the afterglow to be RA(J2000) = 01h 59m 31.17s, Dec(J2000)
= +23d 50m 43.94s with two pixel error 0.46s. Three sigma method was used
to estimate the magnitudes with a calibrator J01593557 +2348527 which is of
V mag ~12.5. After 24 hours of the BAT trigger we do not detect the
afterglow on 7th Jan. at 13:30UT. The details of images and other results
will be in http:/csp.res.in.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23636
SUBJECT: GRB 190106A: NEXT-0.6m and Xinglong-2.16m photometric single powerlaw decay
DATE:    19/01/07 16:48:35 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

Z.P. Zhu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.H. 
Liu (XAO) report:

We monitored the optical afterglow of GRB 190106A (e.g., Sonbas et al., 
GCN 23615) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, 
China and the Xinglong-2.16m telescope.

The observations of NEXT-0.6m started at 13:57:21 UT on 2019-01-06 
(i.e., 0.38 hr post-burst) and ended at 19:48:25 UT on 2019-01-06 (i.e., 
5.97 post-burst), with a series of 60s, 90s, 120s, 200s, and 300s 
exposures in the R-band. The afterglow had R=16.9+/-0.1 mag at the 
beginning, and rather smoothly decayed to R=19.1+/-0.1 mag at the end, 
calibrated with nearby SDSS stars.

The Xinglong-2.16m observations were carried out at 12:54:46 UT on 
2019-01-07, i.e, 23.33 hr post-burst, with 5x360s in the R-band. The 
afterglow has decayed to R=19.9+/-0.1 mag, calibrated with the same 
reference stars.

The joint NEXT-0.6m and Xinglong-2.16m dataset shows that so far the 
afterglow R-band lightcurve has been decaying, and following a single 
powerlaw of F ~ t^-alpha, where alpha~0.64.


GRB_name: GRB190106A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23637
SUBJECT: Konus-Wind observation of GRB 190106A
DATE:    19/01/07 20:22:03 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The  GRB 190106A (Swift detection: Sonbas et al., GCN 23615;
Palmer et al., GCN 23625)
triggered Konus-Wind at T0=48887.602 s UT (13:34:47.602).

The burst light curve shows a multi-peaked structure
which starts at ~T0-5 s and has a total duration of ~79 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.12(-0.17,+0.25)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0-0.044 s,
of 1.81(-0.89,+1.19)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+82.176 s)
is best fit in the 20 keV - 16 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.00(-0.50,+0.63),
and Ep = 171(-42,+90) keV (chi2 = 81/98 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.31 (chi2 = 81/97 dof).

The spectrum near the peak count rate
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 1.2 MeV range
by the power law with exponential cutoff model:
with  alpha = -1.15(-0.50,+0.66),
and Ep = 216(-66,+308) keV (chi2 = 55/60 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -1.85 (chi2 = 55/59 dof).

Assuming the redshift z=1.859 (Xu et al., GCN 23629;
Mao et al., GCN 23630; Schady et al., GCN 23632)
and a standard cosmology model with H_0 = 67.3 km/s/Mpc,
Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is 9.96(-1.55,+2.25)x10^52 erg,
the peak luminosity L_iso is 4.62(-2.28,+3.03)x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is 489(-120,+257) keV, and the rest-frame peak energy of
the 'peak' spectrum, Ep,p,z, is 618(-189, 881) keV.
With these energetics, the burst lies within the 68% prediction bands
for both 'Amati' and 'Yonetoku' relations built for the sample
of 138 long KW GRBs with known redshifts
(Tsvetkova et al., ApJ 850 161, 2017).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190106_T48887/

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


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23638
SUBJECT: GRB 190106A : continued TSHAO optical observations
DATE:    19/01/07 23:21:36 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

I. Reva (FAPHI), A. Pozanenko (IKI),   S. Belkin (IKI), A. Volnova (IKI), 
E. Mazaeva  (IKI),  E. Klunko (ISTP), A. Kusakin (FAPHI), M. Krugov (FAPHI) 
report on behalf of IKI FuN  collaboration:

We continue the observations of  the optical afterglow (e.g. Lipunov  et al. 
GCN 23616, Itoh et al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 
23620, Xin et al. GCN 23622, Quadri et al. GCN 23624, Hu et al. GCN 23627) 
of  the GRB 190106A (Sonbas et al., GCN 23615) with Zeiss-1000  telescope of 
Tien Shan Astronomical Observatory.
We obtained several images in R-filter starting on Jan. 7  (UT) 12:57:20.
Preliminary photometry of the afterglow  is R= 20.07 +/- 0.06  at (UT, mid 
time) 13:40:10 which is compatible with the photometry reported  in GCN 
23636 (Zhu et al.) The photometry is based on nearby USNO-B1.0 stars.


GRB_name: GRB190106A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23640
SUBJECT: GRB 190106A: Mondy optical observations
DATE:    19/01/08 11:50:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), E. Klunko (ISTP), A. Pozanenko (IKI), E. Mazaeva (IKI), A. 
Volnova (IKI), I. Reva (FAPI)  report   on behalf of IKI-FuN:

We observed the optical afterglow (e.g. Lipunov  et al.  GCN 23616, Itoh et 
al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 23620, Xin et al. GCN 
23622, Quadri et al. GCN 23624, Hu et al. GCN 23627)  of  the GRB 190106A 
(Sonbas et al., GCN 23615)  with AZT-33IK telescope of Sayan observatory 
(Mondy).   We started observations on Jan. 06 (UT) 13:53:44, i.e. 19 minutes 
after burst trigger and continued observations on Jan. 07, Jan. 08  in 
R-filter.    Preliminary light curve obtained on Jan. 06 observation can be 
found in  http://grb.rssi.ru/GRB190106A/GRB190106A_LC_R.png

The photometry is based on nearby SDSS  stars
SDSS-DR12_id              R(Lupton)
J015920.22+235150.7 16.475
J015929.35+235237.5 15.774


GRB_name: GRB190109A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23642
SUBJECT: GRB 190109A: Swift detection of a burst
DATE:    19/01/09 05:25:13 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

J.D. Gropp (PSU), S. D. Barthelmy (GSFC),
M. J. Moss (George Washington University), D. M. Palmer (LANL) and
A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 05:12:41 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190109A (trigger=882747).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 33.218, +38.110, which is 
   RA(J2000)  =  02h 12m 52s
   Dec(J2000) = +38d 06' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several peaks
with a total duration of about 70 sec.  The peak count rate
was ~700 counts/sec (15-350 keV), at ~8 sec after the trigger. 

The XRT began observing the field at 05:15:30.6 UT, 168.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 33.20430, 38.10690
which is equivalent to:
   RA(J2000)  = 02h 12m 49.03s
   Dec(J2000) = +38d 06' 24.8"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 40 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 2.5 s image was 2.06e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 180 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
0.05. 

Burst Advocate for this burst is J.D. Gropp (jdg44 AT 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: GRB190109A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23643
SUBJECT: GRB 190109A: Prompt enhanced Swift-XRT position
DATE:    19/01/09 05:49:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using  promptly downlinked XRT event data for GRB 190109A, we find an
enhanced XRT position of the afterglow: RA, Dec: 33.2020, 38.1081 which
is equivalent to:
   RA (J2000)  = 02 12 48.48
   Dec (J2000) = +38 06 29.1
with an uncertainty of 2.0 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/882747.

Position enhancement is 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: GRB190109A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23644
SUBJECT: GRB 190109A: Enhanced Swift-XRT position
DATE:    19/01/09 10:51:14 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1045 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 190109A, 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 = 33.20216, +38.10852 which is equivalent
to:

RA (J2000): 02h 12m 48.52s
Dec (J2000): +38d 06' 30.7"

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: GRB190109A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23645
SUBJECT: GRB 190109A: Swift-XRT refined Analysis
DATE:    19/01/09 11:25:39 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A.
Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), J.P. Osborne
(U. Leicester) and J.D. Gropp report on behalf of the Swift-XRT team:

We have analysed 6.1 ks of XRT data for GRB 190109A (Gropp et al. GCN
Circ. 23642), from 175 s to 13.0 ks after the  BAT trigger. The data
comprise 291 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. 23643).

The late-time light curve (from T0+4.8 ks) can be modelled with a
power-law decay with a decay index of alpha=0.8 (+/-0.3).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.87 (+/-0.04). The
best-fitting absorption column is  9.5 (+1.3, -1.2) x 10^20 cm^-2, in
excess of the Galactic value of 5.1 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.88 (+0.11, -0.09)
and a best-fitting absorption column consistent with the Galactic
value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.5 x 10^-11 (3.8 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.1 (+2.1, -0.0) x 10^20 cm^-2
Galactic foreground: 5.1 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.88 (+0.11, -0.09)

If the light curve continues to decay with a power-law decay index of
0.8, the count rate at T+24 hours will be 0.010 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.6 x
10^-13 (4.0 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/00882747.

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


