{
  "submitter": "Rushikesh Sonawane at IISER, TVM <rushikesh23@iisertvm.ac.in>",
  "circularId": 39682,
  "createdOn": 1741773971887,
  "bibcode": "2025GCN.39682....1S",
  "eventId": "GRB 250223B",
  "body": "R. Sonawane (IISER, TVM), R. Hamburg (USRA) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 10:19:23.76 UT on 23 February 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250223B (trigger 761998768/250223430).\nwhich was also detected by Swift/BAT-GUANO (DeLaunay et al. 2025, GCN 39671).\nThe Fermi GBM on-ground location is consistent with the Swift/BAT position.\n\nThe angle from the Fermi LAT boresight is 56 degrees.\n\nThe GBM light curve consist of multiple spikes with a duration (T90)\nof about 2.4 s (50-300 keV). The time-averaged spectrum\nfrom T0-1.0 to T0+1.7 s is best fit by\na simple power law function with index -1.24 +/- 0.07.\n\nThe event fluence (10-1000 keV) in this time interval is\n(3.9 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured\nstarting from T0+1.2 s in the 10-1000 keV band is 2.9 +/- 1.1 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/\"",
  "submittedHow": "web",
  "subject": "GRB 250223B: Fermi GBM Observation",
  "format": "text/plain"
}