TITLE: GCN CIRCULAR NUMBER: 16790 SUBJECT: GRB 140906B: Fermi GBM Detection of a Long GRB DATE: 14/09/07 19:18:41 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "At 10:18:02.36 UT on the 6th of September 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140906B (trigger 431691485/140906429). The trigger resulted in an Autonomous Repoint Request (ARR) that was accepted. The GBM on-ground location is consistent with the Fermi flight software position. The on-ground calculated location, using the GBM trigger data, is RA = 187.09, DEC = +1.02 (J2000 degrees, equivalent to +16h 33m, +49d 30'), with an uncertainty of 2 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 47 degrees. The GBM light curve consists of several bright emission episodes, with a duration (T90) of about 23 seconds (50-300 keV). The time-averaged spectrum from T0+0 s to T0+23 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -1.4 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 330 +/- 48 keV. The event fluence (10-1000 keV) in this time interval is (9.91 +/- 0.07)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+15 s in the 10-1000 keV band is 11.0+/-0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."