{
  "bibcode": "2017GCN.21404....1S",
  "body": "M. Stanbro and C. Meegan (UAH) report on behalf of the Fermi GBM Team:\n\n\"At 15:18:24.80 UT on 02 August 2017, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 170802A (trigger 523379909 / 170802638).\nThe on-ground calculated location, using the GBM trigger\ndata, is RA = 52.3, DEC = -39.2, with an uncertainty\nof 2.1 degrees (radius, 1-sigma containment,\nstatistical only; there is additionally a systematic\nerror which we have characterized as a core-plus-tail model, with 90% of\nGRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg\nsystematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).\n\nThe trigger resulted in an Autonomous Repoint Request (ARR)\nby the GBM Flight Software owing to the high peak flux\nof the GRB. This ARR was accepted and the spacecraft slewed to the GBM\nin-flight\nlocation. The initial angle from the Fermi LAT boresight to\nthe GBM best location is 41 degrees.\n\nThe GBM triggered on a precursor that\nwas followed ~1 s later by a brighter peak. The\ntotal duration (T90) was about 2 s (50-300 keV).\nThe time-averaged spectrum from T0-0.13 s to T0+2.24 s is\nbest fit by a power law function with an exponential\nhigh-energy cutoff.  The power law index is -0.80 +/- 0.08 and\nthe cutoff energy, parameterized as Epeak, is 952 +/- 200 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(2.70 +/- 0.11)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+1.41 s in the 10-1000 keV band\nis 8.20 +/- 0.27 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak= 670 +/- 163 keV, alpha = -0.70 +/- 0.11 and beta = -2.09 +/-\n0.25.\n\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 21404,
  "createdOn": 1501727102000,
  "email": "mcs0001@uah.edu",
  "subject": "GRB 170802A: Fermi GBM detection",
  "submitter": "Matthew Stanbro at UAH/Fermi  <mcs0001@uah.edu>",
  "eventId": "GRB 170802A"
}