{
  "bibcode": "2017GCN.20792....1X",
  "body": "H.L. Xiao (PSI) , W. Hajdas (PSI) and R. Marcinkowski (PSI)  report on behalf of the POLAR collaboration:\n\nAt 2017-02-28 18:32:56 UT(T0), during a routine on-ground search of data, POLAR detected GRB 170228B,\nwhich was also observed by  Fermi GBM (trigger #509999585).\n\nThe POLAR lightcurve consists of two peaks with duration (T90) of 35.00 +/- 1.00 s measured from T0.\nThe 1.0 s peak flux at T0 + 24.5 s  is equal to 390 +/- 50 counts/sec.\nPOLAR five modules recorded 4680 events from the burst.\nAbove measurements are in the energy range of about 80 - 500 keV.\n\nLC_URL: http://polar.psi.ch/triggers/GRB_170228B_raw.png\n     or http://polar.psi.ch/pub/lc.php?event=GRB+170228B\n\nUsing the best location from Fermi GBM, which is (J2000):\nRA : 355.94 [deg]\nDec: 15.73 [deg]\nthe incident angle in the POLAR coordinate at T0 is:\nTheta: 24.09 [deg]\nPhi: 264.49 [deg]\n\nThe analysis results presented above are preliminary. POLAR is a dedicated Gamma-Ray Burst polarimeter which was launched\non-board the Chinese space laboratory Tiangong-2 (TG-2) on Sep 15, 2016. The energy detection range of POLAR is ~ 50-500 keV.\n\nMore information about POLAR can be found at http://polar.psi.ch/pub ,\nhttp://polar.ihep.ac.cn/en/ and http://isdc.unige.ch/polar/ .\n\nThis message is quotable in publications.",
  "circularId": 20792,
  "createdOn": 1488457700000,
  "email": "hualin.xiao@psi.ch",
  "subject": "GRB 170228B: POLAR Observation",
  "submitter": "Haulin Xiao at PSI/POLAR  <hualin.xiao@psi.ch>",
  "eventId": "GRB 170228B"
}