{
  "createdOn": 1735508276462,
  "bibcode": "2024GCN.38714....1S",
  "body": "L. Scotton (UAH) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 04:13:05.39 UT on 28 December 2024, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 241228B (trigger 757051990/241228176),\nwhich was also detected by Swift/BAT-NITRATES (J. DeLaunay et al. 2024, GCN 38700).\nThe Fermi GBM on-ground location is consistent with the Swift/BAT-NITRATES position.\n\nFollow-up observations report the detection of the potential afterglow \n(Kumar et al. GCN 38684 and GCN 38691; An et al. GCN 38687; Ortega-Casas et al. GCN 38692; \nMohan et al. GCN 38694; Ghosh et al. GCN 38702, Burrows et al. GCN 38713) \nat a redshift z = 2.674 (An et al. GCN 38704).\n\nThe angle from the Fermi LAT boresight is 49 degrees.\n\nThe GBM light curve consists of two emission episodes, with a duration (T90)\nof about 19.5 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.7 to T0+23.4 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.86 +/- 0.01 and the cutoff energy,\nparameterized as Epeak, is 440 +/- 10 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(4.66 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+4.2 s in the 10-1000 keV band is 15.1 +/- 0.3 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/\"",
  "circularId": 38714,
  "subject": "GRB 241228B: Fermi GBM Observation",
  "submittedHow": "web",
  "format": "text/plain",
  "submitter": "Lorenzo Scotton at UAH <lscottongcn@outlook.com>",
  "eventId": "GRB 241228B"
}