{
  "circularId": 42169,
  "eventId": "GRB 251006B",
  "bibcode": "2025GCN.42169....1G",
  "format": "text/plain",
  "subject": "GRB 251006B: Fermi GBM Observation",
  "submittedHow": "web",
  "createdOn": 1759946492722,
  "body": "Matt Godwin (UAH) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 20:05:04.04 UT on 06 October 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 251006B (trigger 781473909/251006837),\nwhich was also detected by Einstein Probe (Yin et al. 2025, GCN 42137) and SVOM/GRM (Wang et al. 2025, GCN 42139).\nThe Fermi GBM on-ground location is consistent with the EP position.\n\nThe angle from the Fermi LAT boresight is 104 degrees.\n\nThe GBM light curve consists of one bright emission with a weaker secondary peak with total duration (T90)\nof about 5.9 s (50-300 keV). The time-averaged spectrum\nfrom T0-2.0 to T0+7.2 s is best fit by\na Band function with Epeak = 330 +/- 14 keV,\nalpha = -0.61 +/- 0.03, and beta = -2.4 +/- 0.1.\n\nThe event fluence (10-1000 keV) in this time interval is\n(2.06 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+0.38 s in the 10-1000 keV band is 26.2 +/- 0.4 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": "Matt Godwin <msg0028@uah.edu>"
}