TITLE: GCN CIRCULAR NUMBER: 20460 SUBJECT: GRB 170112B: POLAR observation DATE: 17/01/15 06:28:51 GMT FROM: Wen Xing at POLAR Xing Wen (IHEP), Yi Zhao (IHEP) and Hancheng Li (IHEP) report on behalf of the POLAR collaboration: At 2017-01-12T23:16:09.00 UT (T0), during a routine on-ground search of data, POLAR detected the GRB 170112B, which was also detected by the Fermi/GBM (trigger 505955774/170112970). The POLAR light curve consists of a single peak, with a duration (T90) of 13.54 s measured from T0-0.06 s. The 1-s peak rate measured from T0+0.00 s is 509.0 cnts/s. The total counts is about 1970 cnts. The above measurements are in the energy range of about 80-500 keV. LC_URL: http://polar.ihep.ac.cn/grb/2017/01/GRB170112B/lc/POLAR_lc_grb170112B.jpg All analysis results presented above are preliminary. POLAR is a dedicated Gamma-Ray Burst polarimeter (50-500 keV) on-board the Chinese space laboratory Tiangong-2 launched on Sep 15,2016. More information about POLAR can be found at http://polar.ihep.ac.cn/en/ , http://isdc.unige.ch/polar/ and http://polar.psi.ch/pub/.