GRB 161203A

Y. Asaoka (Waseda U), A. Yoshida, T. Sakamoto, Y. Kawakubo,
M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
I. Takahashi (IPMU), S. Ozawa, S. Torii (Waseda U), Y. Shimizu,
T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 161203A (Konus-Wind trigger time on 18:41:06.318;
INTEGRAL-SPI/ACS trigger #7641) triggered the CALET Gamma-ray Burst
Monitor (CGBM) at 18:41:07.71 on 3 December 2016.  The burst signal was
seen by all CGBM instruments.  Because of a problem in one of the ground
alert processing script, the GCN notice was not distributed automatically
for this event.

The light curve of the SGM shows at least two overlapping peaks.  The first
peak starts at T-1 sec, peaks at T+0.5 sec and ends at T+2 sec.  The second
peak, which is the brightest peak, starts at T+2 sec, peaks at T+3.5 sec and
ends at T+6 sec.  The T90 duration measured by the SGM data is
5.4 +- 0.8 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1164825510/

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

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

Analysis of AstroSat CZTI data showed clear detection of GRB161203A (CALET detection: T. Sakamoto et al., GCN Circ. 20240
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 ) in the 40-200 keV 
energy range. The light curve shows a single peak structure with main peak at 18:41:10.32 UT, ~3 secs after the CALET trigger at 18:41:07.71 
UT. The measured peak count rate is 334.36 counts/sec above the background in combined data of four quadrants, with a total of 942.45 counts. 
The local mean background count rate was 322.63 counts/sec. Using cumulative rates, we measure a T90 of 8.6 secs.

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.

M. Kole (DPNC/UniGe), N. Produit (ISDC/UniGe),  T. Bernasconi (ISDC/UniGe),
J. C. Sun (IHEP), Y. H. Wang (IHEP), S. L. Xiong (IHEP), Z. H. Li (IHEP),
H. C. Li (IHEP), Y. Zhao (IHEP), T. Batsch(NCBJ), F. Cadoux (DPNC/UniGe),
Y. W. Dong (IHEP), M. Z. Feng (IHEP), M. Y. Ge (IHEP), W. Hajdas (PSI),
Y. Huang (IHEP), Karol Jedrzejczak (NCBJ), F. J. Lu (IHEP), R. Marcinkowski
(PSI), M. Pohl (DPNC/UniGe), A. Rutczynska (NCBJ), D. Rybka (NCBJ),
L. M. Song (IHEP), J. Szabelski (NCBJ), X. Wen (IHEP), B. B. Wu (IHEP),
X. Wu (DPNC/UniGe), H. L. Xiao (PSI), M. Xu (IHEP), J. Zhang
(IHEP), L. Y. Zhang (IHEP), P. Zhang (PSI), S. N. Zhang
(IHEP), Y. J. Zhang (IHEP), A. Zwolinska (NCBJ)
report for he POLAR team:

During a routine on-ground search of data POLAR detected the GRB 161203A,

at 2016-12-03T18:41:07.75 UT(T0). This GRB was also observed by Konus-Wind,

INTEGRAL SPI/ACS (trigger #7641), CALET (GCN #20240
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 ) and Astrosat CZTI (GCN #20241
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 ).

The POLAR light curve consists two peaks with a total duration (T90)

of 4.75 +- 0.25 s measured from T0-0.5 s. The 250-ms peak flux of the

first peak, measured at T0+0.5 s is 1509 cnts/sec. The second stronger

peak measured at T0+3.0 s has a peak flux of 2821 cnts/sec. The

above measurements are in the preliminary calculated energy range

of about 80 - 500 keV.

LC_URL: http://www.isdc.unige.ch/polar/lc/161203A/lcr.png


The analysis results presented above are preliminary as the
instrument calibration is still ongoing.

Preliminary calculations of the MDP show that a
polarimetric measurement of this burst can be attempted.

POLAR is a dedicated Gamma-Ray Burst polarimeter which was
launched on-board the Chinese space laboratory Tiangong-2
(TG-2) on Sep 15, 2016. The energy detection range of POLAR
is ~ 50-500 keV. More information about POLAR can be found
at http://isdc.unige.ch/polar/

This message is quotable in publications.