TITLE: GCN CIRCULAR NUMBER: 20301 SUBJECT: GRB 161212A: POLAR Detection DATE: 16/12/20 08:46:59 GMT FROM: 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. LC_URL: http://www.isdc.unige.ch/polar/lc/161212A/lcr.png 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 http://isdc.unige.ch/polar/ and http://polar.ihep.ac.cn/en/. This message is quotable in publications.