{
  "submittedHow": "web",
  "body": "D. Fernandez (UAH), M. Dafčíková (MUNI) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 10:53:26.00 UT on 01 April 2026, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 260401A (trigger 796733611/260401454),\nwhich was also detected by MAXI (T. Usuki et al. 2026, GCN 44176).\nThe Fermi GBM on-ground location (GCN 44174) is consistent with the MAXI position.\n\nThe angle from the Fermi LAT boresight is 60 degrees.\n\nThe GBM light curve consists of a bright emission episode with multiple peaks with a duration (T90)\nof about 27 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.8 to T0+32.1 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -1.78 +/- 0.01 and the cutoff energy,\nparameterized as Epeak, is 239 +/- 1 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.80 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+7.5 s in the 10-1000 keV band is 21.1 +/- 0.4 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/\"",
  "eventId": "GRB 260401A",
  "submitter": "Daniel Fernandez at University of Alabama In Huntsville (UAH) <df0062@uah.edu>",
  "circularId": 44179,
  "bibcode": "2026GCN.44179....1F",
  "createdOn": 1775086422721,
  "format": "text/plain",
  "subject": "GRB 260401A: Fermi GBM Observation"
}