//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20639 SUBJECT: GRB 170206C: POLAR Observation DATE: 17/02/09 13:49:21 GMT FROM: Radek Marcinkowski at PSI/POLAR R. Marcinkowski (PSI), H. Xiao (PSI) and W. Hajdas (PSI) report on behalf of the POLAR collaboration: At 2017-02-06 11:40:10 UT(T0), during a routine on-ground search of data, POLAR detected GRB 170206C, which was also marginally observed by Integral/SPIACS (trigger 2017-02-06T11:40:10). The POLAR light curve consists of 2 peaks with duration (T90) of 16.0 +/- 0.5 s measured from T0. The 0.5 s peak flux at T0 + 3.2 s is equal to 1400 +/- 100 counts/sec. POLAR recorded about 9700 events from the burst. Above measurements are in the energy range of about 20 - 500 keV, presented light curve is not deadtime corrected. LC_URL: http://polar.psi.ch/triggers/GRB_170206C_raw.png or http://polar.psi.ch/pub/lc.php?event=GRB+170206C 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.