GCN Circular 20272

Y. Zhao (IHEP), M. Z. Feng(IHEP), Z. H. Li (IHEP), Y. H. Wang (IHEP),
J. C. Sun (IHEP), H. C. Li (IHEP), S. L. Xiong (IHEP), T. Batsch(NCBJ),
T. Bernasconi (ISDC/UniGe), F. Cadoux (DPNC/UniGe), Y. W. Dong (IHEP),
M. Y. Ge (IHEP),W.Hajdas (PSI),Y. Huang (IHEP), Karol Jedrzejczak (NCBJ),
M. R. Kole (DPNC/UniGe), F. J. Lu (IHEP), R. Marcinkowski(PSI), 
M. Pohl (DPNC/UniGe), N. Produit (ISDC/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 the POLAR collaboration:

At 2016-12-05T13:27:18UT(T0), during a routine 
on-ground search of data, POLAR detected the GRB 161205A, 
which was also observed by the Fermi/GBM (trigger502637242/161205561).

The POLAR light curve consists of multiple peaks
with a duration (T90) of 26.6s measured from T0-0.66s.
The 1s peak flux, measured from T0+7.00s, is 271.8cnts/s.
The total counts is about 1416cnts. The above measurements
are in the energy range of about 80-500 keV.

LC_URL: http://polar.ihep.ac.cn/grb/2016/GRB161205A/lc/POLAR_lc_grb161205560.jpg

Using the best location from the Fermi/GBM, which is (J2000):
RA:   318.980 [deg]
Dec:  +47.650 [deg]
Err:  5.42    [deg]

the incident angle at T0 in POLAR detector coordinate is:
theta:  63.7 [deg]
phi:    -3.7 [deg]

The analysis results presented above are preliminary.

POLAR is a dedicated Gamma-Ray Burst polarimeter (50-500 keV) on-board 
the Chinese space laboratory Tiangong-2 launched on Sep 15, 2016. More
information about POLAR can be found at http://polar.ihep.ac.cn/en/
, http://isdc.unige.ch/polar/ and http://polar.psi.ch/html/