TITLE: GCN CIRCULAR NUMBER: 11284 SUBJECT: GRB 100915B: Fermi GBM observation DATE: 10/09/15 20:52:50 GMT FROM: Sheila McBreen at MPE Sheila McBreen (UCD/MPE) reports on behalf of the Fermi GBM Team: "At 05:49:39.62 UT on 15 Sept 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100915B (trigger 306222581 / 100915243) which was also detected by INTEGRAL/IBIS (Mereghetti et al. 2010, GCN 11278). The GBM on-ground location is consistent with the INTEGRAL position. The angle from the Fermi LAT boresight is 125 degrees. The GBM light curve consists of one pulse with a duration (T90) of 7.8 (+/- 0.7) s (50-300 keV). The time-averaged spectrum from T0-5.6 s to T0+3.6 s is adequately fit by a power law function with an exponential high energy cutoff. The power law index is 1.35 (+1.63/- 1.10) and the cutoff energy, parameterized as Epeak, is 83.49 (+ 14.50/-9.81) keV (CSTAT 273 for 243 d.o.f.). The event fluence (10-1000 keV) in this time interval is (4.82 +/- 0.06)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-2.56 s in the 10-1000 keV band is 1.85 +/- 0.19 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."