{
  "bibcode": "2022GCN.32574....1B",
  "body": "E. Bissaldi (Politecnico and INFN Bari)\nreports on behalf of the Fermi GBM Team:\n\n\n\"At 11:05:59.071 UT on 21 September 2022, the Fermi Gamma-Ray Burst Monitor (GBM)\ntriggered and located GRB 220921A (trigger 685451164/ 220921462), which was also\ndetected by Fermi-LAT (Pillera et al. 2022, GCN #32568).\n\nThe on-ground calculated location, using the GBM trigger data, is\n\nRA = 66.85, DEC = -40.0\n\n(J2000 degrees, equivalent to 04h 27m, -40d 00'),\nwith a statistical uncertainty of 1 degree (radius, 1-sigma containment,\nstatistical only; there is additionally a systematic error\nwhich we have characterized as a core-plus-tail model,\nwith 90% of GRBs having a 3.7 deg error and a small tail suffering\na larger than 10 deg systematic error.\n[Connaughton et al. 2015, ApJS, 216, 32]).\nThe Fermi GBM on-ground Localization is consistent\nwith the Fermi-LAT position.\n\nThe angle from the Fermi LAT boresight\nat the GBM trigger time is 69 degrees.\n\nThe GBM light curve consists of multiple emission episodes\nwith a duration (T90) of about 210 s (50-300 keV).\nThe time-averaged spectrum from T0 to T0+40 s is\nbest fit by a Band function with Epeak = 142 +/- 4 keV,\nalpha = -0.90 +/- 0.02, and beta = -2.09 +/- 0.02.\n\nThe event fluence (10-1000 keV) in this time interval is\n(5.92 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+11 s in the 10-1000 keV band\nis 36.2 +/- 0.4 ph/s/cm^2.\n\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog:\nhttps://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html\n\nFor Fermi GBM data and info, please visit the official Fermi GBM Support Page:\nhttps://fermi.gsfc.nasa.gov/ssc/data/access/gbm/\"",
  "circularId": 32574,
  "createdOn": 1663866076000,
  "email": "elisabetta.bissaldi@ba.infn.it",
  "subject": "GRB 220921A: Fermi GBM detection",
  "submitter": "Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>",
  "eventId": "GRB 220921A"
}