GCN Circular 20429

R. Marcinkowski (PSI), H. Xiao (PSI) and W. Hajdas (PSI) report on behalf 
of the POLAR collaboration:

At 2016-12-30T12:16:07 UT(T0), during a routine on-ground search of data, 
POLAR detected the GRB 161230A, which was also observed by Fermi GBM 
(trigger # 504792972).

The POLAR light curve consists of 1 peak with duration (T90) of 
3.5 +/- 0.2 s measured from T0. The 0.2 s peak flux at T0 + 2.6 s 
is equal to 390 +/- 60 counts/sec. POLAR recorded 990 +/- 90 events from 
the burst.
Above measurements are in the energy range of about 80 - 500 keV.

LC_URL: http://polar.psi.ch/triggers/GRB_161230A_raw.png
     or http://polar.psi.ch/pub/lc.php?event=GRB+161230A

Using the best location from the Fermi GBM, which is (J2000):
RA : 324.1 [deg]
Dec:  -9.0 [deg]
Err:   3.0 [deg]

the incident angle in the POLAR coordinate at T0 is:
Theta: 47.5 [deg]
Phi:  159.0 [deg]

The analysis results presented above are preliminary. Calibration of the 
instrument is ongoing. 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://polar.psi.ch/pub , 
http://polar.ihep.ac.cn/en/ and http://isdc.unige.ch/polar/ .

This message is quotable in publications.