{
  "bibcode": "2026GCN.43673....1M",
  "subject": "GRB 260208A: Fermi GBM Observation",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of oindabimukherjee@gmail.com",
  "submitter": "oindabimukherjee@gmail.com",
  "createdOn": 1770667775373,
  "eventId": "GRB 260208A",
  "submittedHow": "web",
  "body": "O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 05:07:28.24 UT on 08 February 2026, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 260208A (trigger 792220053/260208214),\nwhich was also detected by Fermi-LAT (F. Longo et al. 2026, GCN 43645), \nSwift XRT (S. Dichiara et al. 2026, GCN 43652), \nand NOT (Dimple et al. 2026, GCN 43662) with a spectroscopic redshift of z = 2.36.\n\nThe Fermi GBM on-ground location is consistent with the Fermi-LAT position.\n\nThe angle from the Fermi LAT boresight is 80 degrees.\n\nThe GBM light curve consists of a single emission episode with a duration (T90)\nof about 35.3 s (50-300 keV). The time-averaged spectrum\nfrom T0-3.6 to T0+66.0 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.87 +/- 0.01 and the cutoff energy,\nparameterized as Epeak, is 460 +/- 0.1 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.50 +/- 0.06)E-04 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+17 s in the 10-1000 keV band is 29.7 +/- 0.4 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak= 328 +/- 1 keV, alpha = -0.76 +/- 0.01 and beta = -2 +/- 0.01.\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": 43673,
  "format": "text/plain",
  "editedOn": 1770741488189,
  "version": 2
}