GCN Circular 33034
E. Bissaldi (Politecnico and INFN Bari) reports on behalf of the Fermi GBM Team: "At 05:50:24.85 UT on 9 December 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 221209A (trigger 692257829 / 221209243). The Fermi GBM Final Real-time Localization is reported in GCN 33031. The angle from the Fermi LAT boresight at the GBM trigger time is 97 degrees. The GBM light curve consists of a single bright emission episode with a duration (T90) of about 4 s (50-300 keV). The time-averaged spectrum from T0 to T0+7 s is best fit by a Band function with Epeak = 325 +/- 12 keV, alpha = -0.62 +/- 0.02, and beta = -2.08 +/- 0.03. The event fluence (10-1000 keV) in this time interval is (3.35 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.2 in the 10-1000 keV band is 67.1 +/- 0.6 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"