{
  "bibcode": "2017GCN.21902....1B",
  "body": "E. Bissaldi (Politecnico & INFN Bari) report on behalf of the Fermi GBM Team:\n\n\n\"At 04:02:11.51 UT on 21 September 2017, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 170921B (trigger 527659336 / 170921168).\n\nThe on-ground calculated location, using the GBM trigger data, is\n\nRA = 134.38, DEC = +46.46\n\n(J2000 degrees, equivalent to 08 h 57m, 46d 27'), with an uncertainty\nof 1.6 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 angle from the Fermi LAT boresight at the GBM trigger time is 101 degrees.\n\nThe GBM light curve consists of a bright FRED-like peak\nwith a duration (T90) of about 34 s (50-300 keV).\nThe time-averaged spectrum from T0 to T0+30 s is\nadequately fit by a Band function with Epeak = 100 +/- 10 keV,\nalpha = -1.2 +/- 0.1, and beta = -2.3 +/- 0.1.\n\nThe event fluence (10-1000 keV) in this time interval is\n(5.4 +/- 0.1)E-5 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+8.1 s in the 10-1000 keV band\nis 38.7 +/- 0.6 ph/s/cm^2.\n\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 21902,
  "createdOn": 1506010753000,
  "email": "Elisabetta.Bissaldi@uibk.ac.at",
  "subject": "GRB 170921B: Fermi GBM detection",
  "submitter": "Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>",
  "eventId": "GRB 170921B"
}