TITLE: GCN CIRCULAR NUMBER: 19265 SUBJECT: GRB 160408A: Fermi GBM detection DATE: 16/04/08 15:23:19 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "At 06:25:43.86 UT on the 8th of April 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160408A (trigger 481789547 / 160408268), which was also detected by Swift (Evans et al. 2008, GCN 19620). 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 about 7 degrees. The GBM light curve consists of two bright, short emission episodes, with a duration (T90) of about 0.9 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.384 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.76 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 914 +/- 184 keV. The event fluence (10-1000 keV) in this time interval is (1.25 +/- 0.08)E-06 erg/cm^2. The 64 ms peak photon flux measured starting from T0+0 s in the 10-1000 keV band, is 12.4 +/- 1.4 ph/s/cm^2. A Band function fits the spectrum equally well, with Epeak = 765 +/- 198 keV, alpha = -0.70 +/- 0.12, and beta = -2.27 +/- 0.41. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."