{
  "subject": "GRB 251201B: Fermi GBM Observation",
  "submittedHow": "web",
  "submitter": "Eva Palafox at INAOE <eva.palafox@gmail.com>",
  "format": "text/plain",
  "body": "\n\nEva Palafox (INAOE) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 16:26:24.22 UT on 01 December 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 251201B (trigger 786299189/251201685),\nwhich was also detected by Swift BAT (M. J. Moss et al. 2025, GCN 42924), and Swift XRT (J.P. Osborne et al. 2025, GCN 42927).\nThe Fermi GBM on-ground location (GCN 42923) is consistent with the Swift BAT position.\n\nThe angle from the Fermi LAT boresight is 119 degrees.\n\nThe GBM light curve consists of a single emission episode with a duration (T90)\nof about 91 s (50-300 keV). \nThe time-averaged spectrum from T0-22.5 to T0+105.5 s is best fit by\na simple power law function with index -1.83 +/- 0.04. \nA power law function with an exponential high-energy cutoff fits equally well with power \nlaw index = -1.71 +/- 0.08 and Epeak = 269.8 +/- 166.0.\n\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.2 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+4.7 s in the 10-1000 keV band is 4 +/- 0.3 ph/s/cm^2.\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/\"",
  "bibcode": "2025GCN.42965....1P",
  "circularId": 42965,
  "createdOn": 1764709049724,
  "eventId": "GRB 251201B"
}