GCN Circular 20602
R. Marcinkowski (PSI), H.L. Xiao (PSI) and W. Hajdas (PSI) report on behalf of the POLAR collaboration: At 2017-02-02 07:19:54 UT(T0), during a routine on-ground search of data, POLAR detected long GRB 170202B, which was also observed by Konus at 07:19:54.107 UT. The POLAR light curve consists of multi peak structure with duration (T90) of 23.0 +/- 0.5 s measured from T0. The 0.5 s peak flux at T0 + 4.8 s is equal to 5000 +/- 120 counts/sec. POLAR recorded about 29700 events from the burst. Above measurements are in the energy range of about 20 - 500 keV. LC_URL: http://polar.psi.ch/triggers/GRB_170202B_raw.png or http://polar.psi.ch/pub/lc.php?event=GRB+170202B 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.