{
  "bibcode": "2017GCN.21383....1S",
  "body": "M. Stanbro and C. Meegan (UAH) report on behalf of the Fermi GBM Team:\n\n\"At 23:03:19.43 UT on 28 July 2017, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 170728B (trigger 522975804 / 170728961)\nwhich was also detected by the Swift/BAT (S. B. Cenko et al. 2017, GCN\n21371)\nand Fermi LAT (M. Yassine et al. 2017, GCN 21380). The GBM on-ground\nlocation\nis consistent with the Swift position.\n\nThe Swift/BAT reported a short GRB in GCN 21371. Fermi GBM sees the\ninitial short peak at trigger time but is followed up by several peaks up\nthe ~50s later.\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 best location is 30 degrees.\n\nThe GBM light curve consists of several episodes\nwith a duration (T90) of about 46 s (50-300 keV).\nThe time-averaged spectrum from T0-.90 s to T0+47.23 s is\nbest fit by a power law function with an exponential\nhigh-energy cutoff.  The power law index is -1.10 +/- 0.10 and\nthe cutoff energy, parameterized as Epeak, is 175 +/- 26 keV\n\nThe event fluence (10-1000 keV) in this time interval is\n(4.59 +/- 0.34)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0-0.13 s in the 10-1000 keV band\nis 12.7 +/- 0.32 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak= 124 +/- 30 keV, alpha = -0.93 +/- 0.19 and beta = -2.12 +/-\n0.22.\n\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 21383,
  "createdOn": 1501343229000,
  "email": "mcs0001@uah.edu",
  "subject": "GRB 170728B: Fermi GBM detection",
  "submitter": "Matthew Stanbro at UAH/Fermi  <mcs0001@uah.edu>",
  "eventId": "GRB 170728B"
}