TITLE: GCN CIRCULAR NUMBER: 17717 SUBJECT: GRB 150416A: Fermi GBM detection DATE: 15/04/17 18:32:07 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM Team: "At 18:33:25.97 on April 16 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150416A (trigger 450902008/150416773) which was also detected by Fermi-LAT (D. Kocevski et al., GCN 17711) The GBM on-ground location, using the Fermi GBM trigger data, is RA = 58.8, Dec = 53.0 (J2000 degrees, equivalent to 3h 55m 00s, 53d 0’), with an uncertainty of 1.9 degrees (radius, 1-sigma containment,statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle of the burst direction to the Fermi LAT boresight is 68 degrees. The GBM light curve consists of two peaks with a duration (T90) of about 33 s (50-300 keV). The time-averaged spectrum from T0+0s to T0+34.8s is well fit by a BAND function with Epeak = 940 +/- 160 keV, Alpha = -0.9 +/- 0.05 and Beta = -2.1 +/- 0.2. The event fluence (10-1000 keV) in this time interval is (1.4 +/- 0.04)E-05 erg/cm^2. The 1.0-sec peak photon flux measured starting from T0+12.8 s in the 10-1000 keV band is 3.8 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."