{
  "bibcode": "2021GCN.29763....1R",
  "body": "O.J. Roberts (USRA/MSFC) and C. Meegan (UAH)\nreport on behalf of the Fermi GBM Team:\n\n\"At 22:04:16.98 UT on the 2nd April 2021, the Fermi Gamma-Ray Burst Monitor (GBM)\ntriggered and located GRB 210402A (trigger 639093861 / 210402920), which was also\ndetected by the Swift/BAT (Page et al. 2021, GCN 29743). The GBM on-ground \nlocation is consistent with the Swift position.\n\nThe angle from the Fermi LAT boresight at the GBM trigger time is 44 degrees.\n\nThe GBM light curve consists of several broad, faint peaks, including emission \nabout 60 s prior to the trigger time. The T90 duration of the event is about \n76 s (50-300 keV). The time-averaged spectrum from T0-60 s to T0+16 s is adequately \nfit by a simple power law function with index -1.34 +/- 0.03.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.699 +/- 0.008)E-6 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0-52.7 s in the 10-1000 keV band is 1.5 +/- 0.2 ph/s/cm^2. \n\nDue to the powering down of Fermi-GBM detectors because of SAA entry about 19 s \nafter the trigger time (note T90), the T90 duration, peak fluxes and fluences \nare lower limits only.\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": 29763,
  "createdOn": 1617653945000,
  "email": "oliver.roberts@nasa.gov",
  "subject": "GRB 210402A: Fermi GBM detection",
  "submitter": "Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>",
  "eventId": "GRB 210402A"
}