{
  "bibcode": "2025GCN.40612....1S",
  "subject": "GRB 250602A: Fermi GBM Observation",
  "createdOn": 1748915255645,
  "submittedHow": "web",
  "eventId": "GRB 250602A",
  "submitter": "Jacob Smith at Fermi-GBM Team <jrs0118@uah.edu>",
  "body": "Jacob Smith (UAH) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\nAt 03:04:31.31 UT on 02 June 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250602A (trigger 770526276/250602128).\nwhich was also detected by Fermi-LAT (A. Holzmann Airasca, et al. 2025, GCN 40611).\nThe Fermi GBM on-ground location is consistent with the Fermi-LAT position.\n\nThe angle from the Fermi LAT boresight is 111 degrees.\n\nThe GBM light curve consists of a single emission episode with a duration (T90)\nof about 14.6 s (50-300 keV). The time-averaged spectrum\nfrom T0+0.003 to T0+8.768 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.9 +/- 0.1 and the cutoff energy,\nparameterized as Epeak, is 120 +/- 10 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.7 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+0.0 s in the 10-1000 keV band is 5.8 +/- 0.3 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak= 102 +/- 22 keV, alpha = -0.7 +/- 0.3 and beta = -2.2 +/- 0.2.\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/",
  "circularId": 40612,
  "format": "text/plain"
}