{
  "submittedHow": "web",
  "submitter": "A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca@unitn.it>",
  "eventId": "GRB 250321A",
  "body": "R. Hamburg (USRA) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 00:42:39.02 UT on 21 March 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250321A (trigger 764210564/250321030),\nwhich was also detected by Swift BAT (Gupta et al. 2025, GCN 39794).\nThe Fermi GBM on-ground location is consistent with the Swift BAT position.\n\nThe angle from the Fermi LAT boresight is 39 degrees.\n\nThe GBM light curve shows one main pulse with a duration (T90)\nof about 6 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.5 to T0+7.2 s is best fit by \na power law function with an exponential high-energy cutoff.\nThe power law index is -0.83 +/- 0.20 and the cutoff energy,\nparameterized as Epeak, is 101 +/- 12 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.04 +/- 0.08)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0-0.13 s in the 10-1000 keV band is 4.7 +/- 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/\"",
  "format": "text/plain",
  "bibcode": "2025GCN.39795....1H",
  "circularId": 39795,
  "createdOn": 1742537063105,
  "subject": "GRB 250321A: Fermi GBM Observation"
}