{
  "bibcode": "2023GCN.33324....1D",
  "body": "S. Dalessi (UAH) and C.Meegan (UAH)\nreport on behalf of the Fermi GBM Team:\n\n\"At 22:32:36.89 UT on 09 February 2023, the Fermi Gamma-Ray Burst Monitor (GBM)\ntriggered and located GRB 230209B (trigger 697674761 / 230209939)\nwhich was also detected by the Swift/BAT-GUANO (G. Raman et al. 2023,\nGCN 33315).\nThe Fermi GBM Final Real-time Localization (GCN #33310) is consistent with the\nlocalization by the IPN network (Kozyrev et al. 2023, GCN 33323).\n\nThe angle from the Fermi LAT boresight at the GBM trigger time is 76 degrees.\n\nThe GBM light curve consists of multiple peaks\nwith a duration (T90) of about 67 s (50-300 keV).\nThe time-averaged spectrum from T0-2.82 s to T0+68.87 s is best fit by\na Band function with Epeak = 183 +/- 6 keV,\nalpha = -0.34 +/- 0.04, and beta = -2.44 +/- 0.09.\n\nThe event fluence (10-1000 keV) in this time interval is\n(3.669 +/- 0.052)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+0.83 s in the 10-1000 keV band\nis 16.4 +/- 0.4 ph/s/cm^2.\n\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": 33324,
  "createdOn": 1676411513000,
  "email": "sd0104@uah.edu",
  "subject": "GRB 230209B: Fermi GBM Observation",
  "submitter": "Sarah Dalessi at UAH  <sd0104@uah.edu>",
  "eventId": "GRB 230209B"
}