{
  "body": "Jacob Smith (UAH), B. Mailyan (Florida Tech) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\nAt 20:10:10.67 UT on 23 August 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250823A (trigger 777672615/250823840),\nwhich was also detected by Swift BAT (M. H. Siegel et al. 2025, GCN 41511), \nand optical follow-up was first reported by Liverpool Telescope (B. P. Gompertz et al. 2025, GCN 41512).\nThe Fermi GBM on-ground location is consistent with the Swift BAT position.\n\nThe angle from the Fermi LAT boresight is 72 degrees.\n\nThe GBM light curve consists of a single emission episode with a duration (T90)\nof about 13 s (50-300 keV). The time-averaged spectrum\nfrom T0-6.1 to T0+10.2 s is best fit by\na simple power law function with index -1.67 +/- 0.05. \nA power law function with an exponential high-energy cutoff fits equally well with power law index = -1.44 +/- 0.17 and Epeak = 206.5 +/- 95.8.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.9 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+1.1 s in the 10-1000 keV band is 1.8 +/- 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 250823A: Fermi GBM Observation",
  "submittedHow": "web",
  "bibcode": "2025GCN.41517....1S",
  "circularId": 41517,
  "createdOn": 1756001354886,
  "eventId": "GRB 250823A",
  "format": "text/plain",
  "submitter": "Jacob Smith at Fermi-GBM Team <jrs0118@uah.edu>"
}