{
  "circularId": 34391,
  "createdOn": 1691890905803,
  "eventId": "GRB 230812B",
  "submittedHow": "web",
  "submitter": "Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>",
  "body": "O.J. Roberts (USRA), C. Meegan (UAH), S. Lesage (UAH), E. Burns (LSU), and S. Dalessi (UAH) \nreport on behalf of the Fermi GBM Team:\n\n\"At 18:58:12.05 UT on 12 August 2023, the Fermi Gamma-Ray Burst Monitor (GBM)\ntriggered and located GRB 230812B (trigger 713559497 / 230812790). The Fermi \nGBM Final Real-time Localization was previously reported (GBM team 2023, GCN 34386). \n\nThe angle from the Fermi LAT boresight at the GBM trigger time is 29 degrees.\n\nThe GBM light curve consists of a FRED-like burst with a duration (T90)\nof about 3 s (10-1000 keV). The time-averaged spectrum over the whole burst\nfrom T0-1s to T0+32 s is best fit by a Band function with Epeak = 273 +/- 3 keV,  \nalpha of -0.80 +/- 0.01 and beta of -2.47 +/-0.02.\n\nThe event fluence (10-1000 keV) in this time interval is\n(2.5201 +/- 0.0002)E-04 erg/cm^2. The 1s peak photon flux measured\nstarting from T0+0.6 s in the 10-1000 keV band is 740 +/- 2 ph/s/cm^2.\n\nDue to a timing glitch in the middle of the burst in the TTE data, this data\ntype had to be reprocessed and consequently, this preliminary report used the \nCSPEC and CTIME data types only, which were unaffected. We note that due\nto the intensity of the burst, pulse pile-up during the burst is highly likely.\nThis analysis is ongoing. \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/\"",
  "bibcode": "2023GCN.34391....1R",
  "subject": "GRB 230812B: Fermi GBM Observation of a very bright burst"
}