TITLE: GCN CIRCULAR NUMBER: 12287 SUBJECT: GRB 110818A: Fermi GBM observation DATE: 11/08/19 23:02:20 GMT FROM: Shaolin Xiong at UAH S. Xiong (UAH) reports on behalf of the Fermi GBM Team: "At 20:37:54.221 UT on 18 August 2011, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 110818A (trigger 335392676 / 110818860 ), which was also detected by the Swift (Markwardt et al. 2011, GCN 12279). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 96 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of multiple peaks with a duration (T90) of about 75 s (50-300 keV). The time-averaged spectrum from T0-16.4 s to T0+57.3 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.33 +/- 0.08 and the cutoff energy, parameterized as Epeak, is 256.3 +/- 55.3 keV. The event fluence (10-1000 keV) in this time interval is (8.2 +/- 0.6)E-6 erg/cm^2. The 64 ms peak photon flux measured starting from T0+22.66 s in the 10-1000 keV band is 5.0 +/- 1.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."