TITLE: GCN CIRCULAR NUMBER: 17579 SUBJECT: GRB 150314A: Fermi GBM observation DATE: 15/03/14 15:30:39 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team: "At 04:54:50.85 UT on 14 Mar 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150314A (trigger 448001693 / 150314205), which was also detected by the Swift (Hagen et al. 2015, GCN 17573) and Fermi LAT (Axelsson et al. 2015, GCN 17576). The GBM on-ground location is consistent with the Swift position. The trigger resulted in an Autonomous Repoint Request (ARR) that was accepted and the spacecraft slewed to the GBM in-flight location. The initial angle from the Fermi LAT boresight is about 50 degrees. The GBM light curve shows a bright single pulse with a duration (T90) of about 10.7 s (50-300 keV). The time-averaged spectrum from T0+0.002 s to T0+13.472 s is best fit by a Band function with Epeak = 311 +/- 5 keV, alpha = -0.60 +/- 0.01, and beta = -2.32 +/- 0.04. The event fluence (10-1000 keV) in this time interval is (8.53 +/- 0.04)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+2.144 s in the 10-1000 keV band is 67.1 +/- 0.5 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."