{
  "submitter": "oindabimukherjee@gmail.com",
  "bibcode": "2025GCN.40473....1M",
  "eventId": "GRB 250516A",
  "circularId": 40473,
  "submittedHow": "web",
  "createdOn": 1747439982234,
  "subject": "GRB 250516A: Fermi GBM Observation",
  "body": "O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 14:35:29.28 UT on 16 May 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250516A (trigger 769098934/250516608).\nwhich was also detected by Swift BAT (A. P. Beardmore et al. 2025, GCN 40467).\nThe Fermi GBM on-ground location is consistent with the Swift BAT position.\n\nThe angle from the Fermi LAT boresight is 36 degrees.\n\nThe GBM light curve consists of two peaks with a duration (T90)\nof about 21.8 s (50-300 keV). The time-averaged spectrum\nfrom T0-1.4 to T0+25.2 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -1.26 +/- 0.07 and the cutoff energy,\nparameterized as Epeak, is 200 +/- 30 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(4.8 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+5.1 s in the 10-1000 keV band is 5.8 +/- 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"
}