{
  "circularId": 35418,
  "submittedHow": "web",
  "submitter": "Peter Veres at University of Alabama in Huntsville <veresp@gmail.com>",
  "bibcode": "2023GCN.35418....1V",
  "subject": "GRB 231222B: Fermi GBM Detection",
  "eventId": "GRB 231222B",
  "createdOn": 1703290076646,
  "body": "P. Veres (UAH), V. Sharma (NASA-GSFC/UMBC) and R. Hamburg (CNRS/IN2P3) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 07:26:02.19 UT on 22 December 2023, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 231222B (trigger 724922767/231222310).\nThe GRB was also detected by Fermi LAT (Di Lalla et al, GCN 35416).\n\nThe angle from the Fermi LAT boresight is 19 degrees.\n\nThe GBM light curve consists of two widely separated pulses with a duration (T90)\nof about 121 s (50-300 keV). The time-averaged spectrum\nfrom T0-5.1 to T0+126.0 s is best fit by\na simple power law function with index -1.55 +/- 0.04.\n\nThe event fluence (10-1000 keV) in this time interval is\n(5.7 +/- 0.6)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+1.7 s in the 10-1000 keV band is 6.0 +/- 0.3 ph/s/cm^2.\n\n\nA power law function with an exponential\nhigh-energy cutoff fits the spectrum equally well.\nThe power law index is -1.09 +/- 0.16 and\nthe cutoff energy, parameterized as Epeak, is 257 +/- 67 keV.\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/\""
}