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GCN Circular 20301

GRB 161212A: POLAR Detection
2016-12-20T08:46:59Z (7 years ago)
Merlin Kole at U of Geneva/POLAR <>
M. Kole (DPNC/UniGe) and R. Marcinkowski (PSI) report on behalf of the POLAR collaboration:

At 2016-12-12T15:38:59.0 UT(T0), during a routine on-ground search of data, POLAR detected the GRB 161212A,
which was also observed by Fermi-GBM (trigger #503249943).

The POLAR light curve consists one peak with a duration (T90) of 1.0 +- 0.25 s measured from T0-0.0 s.
The 250-ms peak flux of the first peak, measured at T0+0.5 s, is 1376 cnts/sec.
The above measurements are in the preliminary calculated energy range of approximately 80 - 500 keV.


Using the best location from the Fermi/GBM, which is (J2000):

RA: 24.94  [deg]

Dec: 68.23  [deg]

Err: 8.5  [deg]

the incident angle in the POLAR coordinate at T0 is:

Alt: -2.2  [deg]

Theta:  46.11 [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 and

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