TITLE: GCN CIRCULAR NUMBER: 17308 SUBJECT: GRB 150118B: Fermi GBM Detection DATE: 15/01/18 23:44:36 GMT FROM: Matthew Stanbro at UAH/Fermi Matthew Stanbro (UAH) reports on behalf of the Fermi GBM Team: "At 09:48:17.77 UT on 18 January 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150118B (trigger 443267300 / 150118409) which was also detected by the Fermi-LAT (Kocevski et al. 2015, GCN 17307) The GBM on-ground location is consistent with the LAT position. The trigger caused GBM to generate an Autonomous Repoint of Fermi. The GBM light curve consists of several episodes with a duration (T90) of about 40 s (50-300 keV). The time-averaged spectrum from T0-4.608 s to T0+49.665 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.89 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 755 +/- 14 keV The event fluence (10-1000 keV) in this time interval is (1.5 +/- 0.007)E-04 erg/cm^2. The 1-sec peak photon flux measured starting from T0+45.8 s in the 8-1000 keV band is 40.7 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."