{
  "subject": "GRB 250808A: Fermi GBM Observation",
  "submittedHow": "web",
  "circularId": 41301,
  "bibcode": "2025GCN.41301....1H",
  "format": "text/plain",
  "submitter": "A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca@unitn.it>",
  "body": "A. Holzmann Airasca (UniTrento and INFN Bari), S. Bala (USRA) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 18:25:12.48 UT on 08 August 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250808A (trigger 776370317/250808768).\nwhich was also detected by SVOM/ECLAIRs (D. Adrien et al. 2025, GCN 41297).\nThe Fermi GBM on-ground location is consistent with the SVOM/ECLAIRs position.\n\nThe angle from the Fermi LAT boresight is 33 degrees.\n\nThe GBM light curve consists of a single variable emission episode with a duration (T90)\nof about 49 s (50-300 keV). The time-averaged spectrum\nfrom T0-6.1 to T0+51.2 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -1.1 +/- 0.2 and the cutoff energy,\nparameterized as Epeak, is 70 +/- 7 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(2.7 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+45 s in the 10-1000 keV band is 2.5 +/- 0.2 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak= 55 +/- 9 keV, alpha = -0.7 +/- 0.3 and beta = -2.5 +/- 0.3.\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/\"",
  "createdOn": 1754742881160,
  "eventId": "GRB 250808A"
}