TITLE: GCN CIRCULAR NUMBER: 16971 SUBJECT: GRB 141028A: Fermi GBM detection DATE: 14/10/28 19:00:19 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "At 10:54:46.78 UT on 28 October 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141028A (trigger 436186489 / 141028455), which was also detected by the LAT (Bissaldi et al. 2014, GCN 16969). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with the LAT location. The trigger resulted in an Autonomous Repoint Request (ARR) that was accepted and the spacecraft slewed to the GBM in-flight location. The on-ground calculated location, using the GBM trigger data, is RA = 316.32, DEC = +1.67, with an uncertainty of 1.0 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 from the Fermi LAT boresight is about 19 degrees. The GBM light curve consists of a single episode with a duration (T90) of about 31.5 s (50-300 keV). The time-averaged spectrum from T0+0s to T0+31.7s is well fit by a Band function with Epeak = 249.9 (+/-12.6) keV, alpha = -0.71 +/- 0.03 , and beta = -1.93 (+/-0.03). The event fluence (10-1000 keV) in this time interval is (3.478 +/- 0.009)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+12.6 s in the 10-1000 keV band is 17.3 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."