{
  "bibcode": "2021GCN.29361....1L",
  "body": "S. Lesage (UAH), R. Dunwoody (UCD), J. Mangan (UCD), C. Meegan (UAH)\nreport on behalf of the Fermi GBM Team:\n\n\"At 07:10:44.70 UT on 20 January 2021, the Fermi Gamma-Ray Burst Monitor\n(GBM)\ntriggered and located GRB 210120A (trigger 632819449 / 210120.299),\nthe optical counterpart for which was detected by MASTER (Lipunov et al.\n2021,\nGCN 29339) and confirmed (Pozanenko et al. 2021, GCN 29341; Dimple et al.\n2021,\nGCN 29345). The GBM Fermi GBM Final Real-time Localization (GCN 29334) is\nconsistent\nwith the MASTER OT follow-up observations.\n\nThe angle from the Fermi LAT boresight at the GBM trigger time is 82\ndegrees.\n\nThe GBM light curve consists of a single peak\nwith a duration (T90) of about 22.2 s (50-300 keV).\nThe time-averaged spectrum from T0-0.32 s to T0+22.21 s is\nbest fit by a power law function with an exponential\nhigh-energy cutoff. The power law index is -0.62 +/- 0.12 and\nthe cutoff energy, parameterized as Epeak, is 94 +/- 6 keV\n\nThe event fluence (10-1000 keV) in this time interval is\n(2.9 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+ 2.6 s in the 10-1000 keV band\nis 3.6 +/- 0.2 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak= 95 +/- 6 keV, alpha = -0.63 +/- 0.12 and beta = -29 +/- 6E12.\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\nPage:\nhttps://fermi.gsfc.nasa.gov/ssc/data/access/gbm/\"",
  "circularId": 29361,
  "createdOn": 1611711591000,
  "email": "sjl0014@uah.edu",
  "subject": "GRB 210120A: Fermi GBM detection",
  "submitter": "Stephen Lesage at Fermi-GBM Team  <sjl0014@uah.edu>",
  "eventId": "GRB 210120A"
}