TITLE: GCN CIRCULAR NUMBER: 13671 SUBJECT: GRB 120817B: Fermi GBM detection DATE: 12/08/17 21:29:55 GMT FROM: Shaolin Xiong at UAH Shaolin Xiong (UAH) reports on behalf of the Fermi GBM Team: "At 04:02:29.723 UT on 17 August 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 120817B (trigger 366868952 / 120817168), which was also located by IPN (S. Golenetskii et al. 2012, GCN 13670). The GBM on-ground location is consistent with the IPN position. The angle from the Fermi LAT boresight is 59 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve shows a single pulse with a duration (T90) of about 0.192 s (50-300 keV). The time-averaged spectrum from T0-0.032 s to T0+0.064 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.65 +/- 0.05 and the cutoff energy, parameterized as Epeak, is 1377 +/- 173 keV. The event fluence (10-1000 keV) in this time interval is (1.85 +/- 0.06)E-6 erg/cm^2. The 64 ms peak photon flux measured starting from T0+0.0 s in the 10-1000 keV band is 46.6 +/- 1.6 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."