{
  "body": "O. Mukherjee (USRA), C. Meegan (UAH), U. Pathak (IIT Bombay) and L. Scotton (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 07:08:21.91 UT on 11 October 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 251011B (trigger 781859306/251011297).\nwhich was also detected by Swift BAT (A. D'Ai et al. 2025, GCN 42197), \nand Swift XRT (P.A. Evans et al. 2025, GCN 42201).\nThe Fermi GBM on-ground location is consistent with the Swift BAT position.\n\nThe angle from the Fermi LAT boresight is 81.8 degrees.\n\nThe GBM light curve consists of a single pulse with a duration (T90)\nof about 35 s (50-300 keV). The time-averaged spectrum\nfrom T0-8.0 to T0+26.5 s is best fit by\na Band function with Epeak = 36 +/- 5 keV,\nalpha = 0.4 +/- 0.7, and beta = -2.2 +/- 0.1.\n\nThe event fluence (10-1000 keV) in this time interval is\n(3.3 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+0.58 s in the 10-1000 keV band is 3 +/- 0.2 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/\"",
  "subject": "GRB 251011B: Fermi GBM Observation",
  "eventId": "GRB 251011B",
  "bibcode": "2025GCN.42204....1M",
  "circularId": 42204,
  "submittedHow": "web",
  "submitter": "oindabimukherjee@gmail.com",
  "format": "text/plain",
  "createdOn": 1760228815149
}