GCN Circular 19380
B. Mailyan (UAH) and K. Toelge (MPE) report on behalf of the Fermi GBM Team: "At 13:36:32.008 UT on 03 May 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160503A (trigger 483975396 / 160503567), which was also detected by the LAT (N. Omodei et al. 2016, GCN 19379) The GBM on-ground location is consistent with the LAT position. The angle from the Fermi LAT boresight at the GBM trigger time is 25 degrees. The GBM light curve consists of two peaks with a duration (T90) of about 59.4 s (50-300 keV). The time-averaged spectrum from T0-4.9 s to T0+28.9 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.28 +/- 0.14 and the cutoff energy, parameterized as Epeak, is 138.7 +/- 33.5 keV. The event fluence (10-1000 keV) in this time interval is (2.15 +/- 0.25)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.58 s in the 8-1000 keV band is 2.5 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."