TITLE: GCN CIRCULAR NUMBER: 33030 SUBJECT: GRB 221206B: Fermi GBM observation DATE: 22/12/08 10:24:03 GMT FROM: Christian Malacaria at ISSI C. Malacaria (ISSI) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 12:22:47.36 UT on 06 December 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 221206B (trigger 692022172 / 221206516). The GBM Final Real-time Localization was reported in GCN 33023. The event was also detected by the Swift/BAT-GUANO (DeLaunay et al. 2022, GCN 33027) at a consistent position. The angle from the Fermi LAT boresight at the GBM trigger time is 121 degrees. The GBM light curve consists of two main peaks with a duration (T90) of about 8 s (50-300 keV). The time-averaged spectrum from T0-0 s to T0+5.9 s is best fit by a Band function with Epeak = 151 +/- 6 keV, alpha = -0.36 +/- 0.06, and beta = -3.1 +/- 0.2 The event fluence (10-1000 keV) in this time interval is (2.19 +/- 0.05)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+7.5 s in the 10-1000 keV band is 26.7 +/- 0.7 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/ "