{
  "eventId": "GRB 251005C",
  "submittedHow": "web",
  "subject": "GRB 251005C: Fermi GBM Observation",
  "bibcode": "2025GCN.42118....1S",
  "circularId": 42118,
  "format": "text/plain",
  "createdOn": 1759722394901,
  "body": "Jacob Smith (UAH), B. Mailyan (Florida Tech) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 16:06:54.00 UT on 05 October 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 251005C (trigger 781373219/251005671),\nwhich was also detected by Swift BAT (K. L. Page et al. 2025, GCN 42113).\nThe Fermi GBM on-ground location is consistent with the Swift BAT position.\n\nThe angle from the Fermi LAT boresight is 98 degrees.\n\nThe GBM light curve consists of a double emission episode with a duration (T90)\nof about 6 s (50-300 keV). The time-averaged spectrum\nfrom T0+0.003 to T0+5.248 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.9 +/- 0.1 and the cutoff energy,\nparameterized as Epeak, is 2136 +/- 866 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(3.2 +/- 0.2)E-06 erg/cm^2. The 64-millisec peak photon flux measured\nstarting from T0+0.58 s in the 10-1000 keV band is 6.1 +/- 1.2 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/\"",
  "submitter": "Jacob Smith at Fermi-GBM Team <jrs0118@uah.edu>"
}