{
  "body": "A. Holzmann Airasca (UniTrento and INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:\n\n\"At 06:41:54.06 UT on 10 May 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250510B (trigger 768552119/250510279).\nwhich was also detected by Swift/BAT-GUANO (S. Ronchini et al. 2025, GCN 40419).\nThe Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position.\n\nThe angle from the Fermi LAT boresight is 103 degrees.\n\nThe GBM light curve consists of main emission episode with a duration (T90)\nof about 35 s (50-300 keV). The time-averaged spectrum\nfrom T0+0.51 to T0+35.58 s is \nbest fit by a Band function with Epeak = 147 +/- 15 keV,\nalpha = 0.71 +/- 0.38, and beta = -2.79 +/- 0.49.\n\nThe event fluence (10-1000 keV) in this time interval is\n(4.79 +/- 0.32)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+2.01 s in the 10-1000 keV band is 2.44 +/- 0.22 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/\"",
  "submitter": "A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca@unitn.it>",
  "circularId": 40427,
  "eventId": "GRB 250510B",
  "submittedHow": "web",
  "bibcode": "2025GCN.40427....1H",
  "subject": "GRB 250510B: Fermi GBM Observation",
  "createdOn": 1746941624349,
  "format": "text/plain"
}