TITLE: GCN CIRCULAR NUMBER: 17295 SUBJECT: GRB 150110B: Fermi GBM Detection DATE: 15/01/11 06:03:26 GMT FROM: Matthew Stanbro at UAH/Fermi Matthew Stanbro (UAH) report on behalf of the Fermi GBM Team: "At 22:08:31.91 UT on 10 January 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150110B (trigger 442620514 / 150110923) which was also detected by the Swift/BAT (Evans et al. 2015, GCN 17291) The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 22 degrees. The GBM light curve consists of 1 peak with a duration (T90) of about 2 s (50-300 keV). The time-averaged spectrum from T0-1.54 s to T0+1.54 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.98 +/- 0.22 and the cutoff energy, parameterized as Epeak, is 122.5 +/- 24.3 keV The event fluence (10-1000 keV) in this time interval is (5.30 +/- 0.61)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.06 s in the 8-1000 keV band is 2.33 +/- 0.21 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."