GCN Circular 20665
Y.H. Wang (IHEP), M.Z. Feng (IHEP), Y. Zhao (IHEP), report on behalf of the POLAR collaboration: At 2017-02-10T02:47:37 UT (T0), during a routine on-ground search of data, POLAR detected the long-duration GRB 170210A, which was also reported by the Fermi/GBM (O.J. Roberts et al, GCN Circ. 20660) and IPN Triangulation(K. Hurley et al, GCN Circ. 20661), and also detected by Konus-Wind. The POLAR light curve shows a long burst consists of multiple peaks, with a duration (T90) of 62.27 s measured from T0+13.12 s. The 1-s peak rate measured from T0+41.0 s is 6673.75cnts/s. The total counts is about 106099 cnts. LC_URL: http://polar.ihep.ac.cn/grb/2017/02/GRB170210A/lc/POLAR_lc_grb170210A.png The above results are not dead time corrected. The above measurements are in the energy range of about 20-500 keV. Using the best location from the IPN Triangulation, which is (J2000): RA: 226.055 [deg] Dec: -65.101 [deg] Err: 1731 [sq. arcmin](3 sigma) the incident angle in POLAR coordinate at T0 is: theta: 80.6 [deg] phi: 130.9 [deg] The Minimum Detectable Polarization(MDP) for this burst is estimated to be ~7.3% [1-sigma, statistical only]. 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/.