GCN Circular 8107
Andreas von Kienlin, Sheila McBreen and Elisabetta Bissaldi (MPE) report on behalf of the GLAST Burst Monitor Team: "At 12:04:18 UT on 2008 Aug 16, the GLAST Burst Monitor (GBM) triggered and located GRB 080816 (GBM 080816.503 / trigger 240581059). The on-ground calculated location, using the GBM trigger data, is RA = 156.9, Dec = +54.60 (J2000 degrees) (equivalent to J2000 10h 28m, +54d 36'), with an uncertainty of 2.3 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 Large Area Telescope (LAT) boresight is 55 degrees at ~T+35 sec. This GRB has a duration of approximately 70 s and contains 4 peaks. The preliminary averaged time spectrum in the 10 keV to 500 keV energy band from T-1 to T+69 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -0.57 +/-0.14 and the cutoff energy, parameterized as Epeak, is 146.7 +/-14.5 keV, with a reduced chi-square of 1.2 for 291 degrees of freedom. The fluence in the 50-300 keV band is (1.86 +/- 0.20) x 10^-5 erg/cm2. The 1-sec photon flux measured from T+35 sec in the 50-300 keV band is 3.48 +/-0.66 ph/cm2/sec. All the quoted errors are at the 90% confidence level. These spectral analysis results presented above are preliminary; the final results will be published in the GBM GRB Catalog."