{
  "bibcode": "2021GCN.30779....1V",
  "body": "P. Veres (UAH) and O. J. Roberts (USRA) report\non behalf of the Fermi-GBM Team:\n\n\"Swift-BAT detected GRB 210905A at 00:12:41 UT (GCN 30765). There was no\nFermi-GBM onboard trigger around the event.\n\nThe GBM targeted search [1], the most sensitive, coherent search for\nGRB-like signals was run from +/-30 s around the BAT trigger time.  A\ntransient source was identified whose most significant timescale according\nto the search is 8.192 s with a false alarm rate of 1.3e-5 Hz, and a\nlocation consistent with the Swift-BAT event, using the standard search\nprotocol with a S/N of 13.  The GBM targeted search event was found with\nthe highest significance with a \"normal\" spectral template (Band function\nwith Epeak = 230 keV, alpha = -1.0, beta = -2.3).\n\nThe GBM light curve consists of multiple overlapping pulses. The\ntime-averaged spectrum from T0-26 s to T0+16 s is best fit by a power law\nfunction with an exponential high-energy cutoff (T0 is 2021-09-05 00:12:41\nUT). The power law index is -1.19 +/- 0.13 and the cutoff energy,\nparameterized as Epeak, is 204 +/- 45 keV.\n\nThe event fluence (10-1000 keV) in this time interval for the best fitting\nmodel is (6.08 +/- 0.59)E-6 erg/cm^2. Using the redshift z=6.318 reported\nby Tanvir et al. (GCN 30771), we derive an isotropic equivalent energy in\nthe 1-10,000 keV range of (4.25 +/- 0.41)E+53 erg.\n\nThis analysis is preliminary.\n\n[1] Goldstein et al. 2019 arXiv:1903.12597\n\"",
  "circularId": 30779,
  "createdOn": 1630906799000,
  "email": "veresp@gmail.com",
  "subject": "Fermi GBM Sub-Threshold Detection of GRB 210905A",
  "submitter": "Peter Veres at UAH  <veresp@gmail.com>",
  "eventId": "GRB 210905A"
}