TITLE: GCN CIRCULAR NUMBER: 15064 SUBJECT: GRB 130803A; Fermi GBM observation DATE: 13/08/04 00:35:04 GMT FROM: Hoi-Fung Yu at MPE Subject: GRB 130803A: Fermi GBM observation Hoi-Fung Yu (MPE) report on behalf of the Fermi GBM Team: "At 10:02:53.75 UT on 03 Aug 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130803A (trigger 397216976 / 130803419), which was also detected by the Swift BAT and XRT (Page et al. 2013, GCN 15059). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 86 degrees. The GBM light curve consists of a single pulse, with a duration (T90) of about 7.6 s (50-300 keV). The time-averaged spectrum from T0-1.0 s to T0+4.9 s is adequately fit by a power law function with an exponential high-energy cutoff. The power-law index is -0.85 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 141.6 +/- 12.2 keV. The event fluence (10-1000 keV) in this time interval is (2.5 +/- 0.1)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.6 s in the 10-1000 keV band is 7.1 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."