TITLE: GCN CIRCULAR NUMBER: 20633 SUBJECT: GRB 170208A: Fermi GBM Detection DATE: 17/02/09 00:05:14 GMT FROM: Oliver J Roberts at USRA/NASA O.J. Roberts (USRA/NASA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 18:11:16.40 UT on the 8th of February 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170208A (trigger 508270281 / 170208758), which was also detected by Swift (A. Cholden-Brown et al. 2017, GCN 20631). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time using the Swift-XRT position is 117 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of a long GRB with several episodes of bright emission over a duration (T90) of about 7 s (50-300 keV). The time-averaged spectrum from T0+0 s to T0+7.2 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.92 +/- 0.09 and the cutoff energy, parameterized as Epeak is 246.9 +/- 30.5 keV The event fluence (10-1000 keV) in this time interval is (3.10 +/- 0.19)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.13 s in the 10-1000 keV band is 8.1 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."