{
  "subject": "GRB 251018A: Fermi GBM Observation",
  "createdOn": 1760824437668,
  "eventId": "GRB 251018A",
  "submittedHow": "web",
  "body": "B. Hristov (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:\n\n\"At 03:12:00.63 UT on 18 October 2025 , the Fermi Gamma-Ray Burst Monitor (GBM)\ntriggered and located GRB 251018A (trigger 782449925 / 251018133),\nwhich was also detected by the Swift/XRT (R. Gupta et al. 2025, GCN 42343)\nThe GBM on-ground location is consistent with the Swift position.\n\nThe angle from the Fermi LAT boresight at the GBM trigger time is 42 degrees.\n\nThe GBM light curve consists of multiple peaks,\nwith a duration (T90) of about 27.1 s  (50-300 keV).\nThe time-averaged spectrum from T0-6.1 s to T0+21.5 s\nis well fit by a power law function with an exponential high-energy cutoff.\nThe power law index is -0.91 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 715 +/- 162 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(6.8 +/- 0.3)E-6 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+3 s in the 10-1000 keV band 0.95 +/- 0.04 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": "Glowbug DEV <boyan.a.hristov@nasa.gov>",
  "bibcode": "2025GCN.42364....1H",
  "format": "text/plain",
  "circularId": 42364
}