TITLE: GCN CIRCULAR NUMBER: 15935 SUBJECT: GRB 140306A: Fermi GBM detection DATE: 14/03/06 11:44:43 GMT FROM: Gerard Fitzpatrick at UCD G. Fitzpatrick (UCD) and M. Stanbro (UAH) report on behalf of the Fermi GBM Team: At 03:29:44.95 UT on 06 March 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140306A (trigger 415769387/140306146). 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 = 31.3 , DEC = +45.9 (J2000 degrees, equivalent to 02h 05m, +45d 54.0'), with an uncertainty of 1.00 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The initial angle from the Fermi LAT boresight was 61 degrees. The GBM light curve consists of several peak with a duration (T90) of about 68 s (50-300 keV). The time-averaged spectrum from T0-1.21601 s to T0+69.6s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -1.10 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 1580 +/- 100 keV The event fluence (10-1000 keV) in this time interval is (6.9 +/- 0.06)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.5 s in the 10-1000 keV band is 11.7 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog.