{
  "format": "text/plain",
  "bibcode": "2025GCN.42037....1D",
  "eventId": "GRB 251001A",
  "circularId": 42037,
  "body": "M. Dafcikova (MUNI), S. Lesage (UAH) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 02:40:56.95 UT on 01 October 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 251001A (trigger 780979261/251001112).\n\nThe on-ground calculated location, using the Fermi GBM trigger data,\nis RA = 224.44, Dec = -56.23 (J2000 degrees, equivalent to\nJ2000 14h 57m, -56d 13'), with a statistical uncertainty of 1.79 degrees.\n(radius, 1-sigma containment, statistical only; there is additionally a\nsystematic error which we have characterized as a mixture of two Gaussians,\none with a radius of 1.8 degrees (52% contribution) and one with a radius\nof 4.1 degrees (47% contribution) [A. Goldstein et al. 2020, ApJ, 895, 1]).\n\nThe angle from the Fermi LAT boresight is 116 degrees.\n\nThe GBM light curve consists of two peaks with a duration (T90)\nof about 7 s (50-300 keV). The time-averaged spectrum\nfrom T0+0.003 to T0+8.640 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.63 +/- 0.08 and the cutoff energy,\nparameterized as Epeak, is 138 +/- 7 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(4.4 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+6.0 s in the 10-1000 keV band is 24.8 +/- 0.6 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 251001A: Fermi GBM Detection",
  "submitter": "Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>",
  "createdOn": 1759328123891,
  "submittedHow": "web"
}