GCN Circular 8290
A. von Kienlin (MPE), E. Bissaldi (MPE), S. McBreen (MPE) report on behalf of the Fermi GBM Team: "At 06:25:48 UT on 20 September 2008, the Fermi Gamma-ray Burst Monitor triggered and located GRB 080920 (trigger 243584749 / 080920268). The on-ground calculated location using the Fermi GBM trigger data is RA = 124.6, Dec = 1.6 (equivalent to J2000 08h 18m, 01d 36'), with a statistical uncertainty of 3.4 degrees (radius, 1-sigma containment; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 16 degrees. This long GRB comprises one FRED like pulse, starting at T0-6 s. T90 (25-1000 keV) is about 85 s. The time-averaged spectrum from T0-6 to T0+79 s is adequately fit by a power law model with index -1.42 +/- 0.06. It can also be fit with a power law function with an exponential high energy cutoff. The cutoff energy, parameterized as Epeak, is 162 +/- 35 keV. In this case the power law index is poorly constrained (-0.63 +/- 0.25). The fluence in the 25-1000 keV band is 2.4 (+/- 0.5) E-06 erg/cm2 and the peak flux (25-1000 keV) on the 1 s timescale is 1.29 (+/- 0.14) ph/cm2/s. The spectral analysis results presented above are preliminary; final results will be published in the Fermi GBM GRB Catalog."