GCN Circular 17783
Bin-Bin Zhang (UAH) report on behalf of the Fermi GBM team: "At 14:15:31.22 on April 26 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150426A (trigger 451750534/150426594). The GBM on-ground location, using the Fermi GBM trigger data, is RA = 17.6, Dec = -30.2 with an uncertainty of 1.5 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 136 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 23 s (50-300 keV). The time-averaged spectrum from T0+0s to T0+23 s is well fit by a BAND function with Epeak = 109.9 +/- 10.6 keV, alpha = -1.0 +/- 0.1 and Beta = -2.3 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (1.15 +/- 0.04)E-05 erg/cm^2. The 1.0-sec peak photon flux measured starting from T0+13.8 s in the 10-1000 keV band is 22.1 +/- 0.7 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."