{
  "eventId": "GRB 251121A",
  "submitter": "Angus Jameson <abj0023@uah.edu>",
  "submittedHow": "web",
  "createdOn": 1764189152386,
  "bibcode": "2025GCN.42846....1B",
  "body": "S. Bala (USRA), A. Jameson (UAH), and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 16:30:58.99 UT on 21 November 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 251121A (trigger 785435463/251121688),\nwhich was also detected by Swift/BAT-GUANO (DeLaunay et al. 2025 GCN 42795).\nThe Fermi GBM on-ground location (GCN 42790) is consistent with the Swift/BAT-GUANO position.\n\nThe angle from the Fermi LAT boresight is 100 degrees.\n\nThe GBM light curve single peak with a duration (T90)\nof about 0.3 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.2 to T0+0.3 s is best fit by\na simple power law function with index -1.31 +/- 0.07.\n\nThe event fluence (10-1000 keV) in this time interval is\n(2.8 +/- 0.3)E-07 erg/cm^2. The 64-ms peak photon flux measured\nstarting from T0-0.064 s in the 10-1000 keV band is 5 +/- 1 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/\"",
  "circularId": 42846,
  "subject": "GRB 251121A: Fermi GBM Observation",
  "format": "text/plain"
}