TITLE: GCN CIRCULAR NUMBER: 18299 SUBJECT: GRB 150912A: Fermi GBM observation DATE: 15/09/12 21:34:34 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (INFN Bari) reports on behalf of the Fermi GBM Team: "At 10:37:38.70 UT on 12 September 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150912A (trigger 463747062/150912443), which was also detected by INTEGRAL (Mereghetti et al. 2015, GCN 18291). The GBM on-ground location is consistent with the INTEGRAL position. The angle from the Fermi-LAT boresight at the GBM trigger time is 67 degrees. The GBM light curve consists of a single peak with a duration (T90) of about 30 s (50-300 keV). The time-averaged spectrum from T0-6 s to T0+22 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.11 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 250 +/- 40 keV. The event fluence (10-1000 keV) in this time interval is (4.5 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux, measured starting from T0+2.2 s in the 10-1000 keV band, is 2.82 +/- 0.25 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."