{
  "submittedHow": "web",
  "body": "Matt Godwin (UAH) and C.Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:\n\n\"At 23:36:05.78 UT on 21 January 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250121A (trigger 759195370/250121983).\nwhich was also detected by Fermi-LAT (Holzmann Airasca et al. 2025, GCN 39010).\nThe Fermi GBM on-ground location is consistent with the Fermi-LAT position. (Fermi GBM Team et al. 2025, GCN 39006)\n\nThe angle from the Fermi LAT boresight is 15 degrees.\nThis burst was also independently detected by INTEGRAL SPI-ACS.\nThe GBM light curve consists of one peak with a duration (T90)\nof about 5.2 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.4 to T0+5.8 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.65 +/- 0.05 and the cutoff energy,\nparameterized as Epeak, is 230 +/- 10 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(5.8 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+0.32 s in the 10-1000 keV band is 14.0 +/- 0.3 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak= 210 +/- 20 keV, alpha = -0.59 +/- 0.07 and beta = -2.5 +/- 0.3.\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/\"",
  "eventId": "GRB 250121A",
  "createdOn": 1737664421172,
  "circularId": 39018,
  "format": "text/plain",
  "subject": "GRB 250121A: Fermi GBM Observation",
  "submitter": "Matt Godwin <msg0028@uah.edu>",
  "bibcode": "2025GCN.39018....1G"
}