{
  "bibcode": "2022GCN.32636....1V",
  "body": "P. Veres (UAH),  E. Burns (LSU), E. Bissaldi (Politecnico and INFN\nBari), S. Lesage (UAH), O. Roberts (USRA)\nreport on behalf of the Fermi GBM Team:\n\n\"At 2022-10-09 13:16:59.000 UT on 9 October 2022, the Fermi Gamma-Ray\nBurst Monitor (GBM) triggered and located GRB 221009A (trigger\n687014224 / 221009553).\n\nThis event, if it is a GRB, it is the brightest among the GBM detected\nGRBs. If it is not a GRB then it is a rare transient event. Follow-up\nacross all wavelengths is encouraged.\n\nThe on-ground calculated location, using the GBM trigger\ndata, is RA = 290.4, DEC = 22.3 (J2000 degrees,\nequivalent to 19 h 22 m, 22 d 15 '), with a statistical uncertainty\nof 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\nThis location is consistent with the Swift J1913.1+1946 localization\n(Dichiara et al. GCN 32632)  though it precedes the Swift trigger by\nan hour.\n\n\nThe angle from the Fermi LAT boresight at the GBM trigger time is 76 degrees.\n\nThe GBM light curve consists of an initial ~10 s long pulse, followed\nby an extraordinarily bright episode at ~180 s after the trigger time,\nlasting at least 100 seconds.\n\n\n\nThe 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": 32636,
  "createdOn": 1665348876000,
  "email": "veresp@gmail.com",
  "subject": "GRB 221009A: Fermi GBM detection of an extraordinarily bright GRB",
  "submitter": "Peter Veres at UAH  <veresp@gmail.com>",
  "eventId": "GRB 221009A"
}