TITLE: GCN CIRCULAR NUMBER: 23548 SUBJECT: GRB 181222A: Fermi GBM observation DATE: 18/12/22 17:37:52 GMT FROM: Peter Veres at UAH P. Veres (UAH) and E. Bissaldi (Politecnico & INFN Bari) report on behalf of the Fermi GBM Team: "At 06:41:34.25 UT on 22 December 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 181222A (trigger 567153699 / 181222279) which was also detected by MAXI/GSC (Sakamaki et al., GCN 23547). The GBM on-ground location is consistent with the MAXI position. The angle from the Fermi LAT boresight at the GBM trigger time is 89 degrees. The GBM light curve shows four separate pulses with a duration (T90) of about 131 s (50-300 keV). The time-averaged spectrum from T0-1 s to T0+151 s is adequately fit by a Band function with Epeak = 264 +/- 32 keV, alpha = -0.95 +/- 0.04, and beta = -1.47 +/- 0.01. The event fluence (10-1000 keV) in this time interval is (1.83 +/- 0.01)E-4 erg/cm^2. The 1-sec peak photon flux measured starting from T0+94.9 s in the 10-1000 keV band is 74.7 +/- 0.7 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."