TITLE: GCN CIRCULAR NUMBER: 8505 SUBJECT: GRB 081109: Fermi GBM detection DATE: 08/11/09 15:56:47 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 07:02:02.42 UT on 09 November 2008, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 081109 (trigger 247906923 / 081109293), which was also detected by the SWIFT (S. Immler et al. 2008, GCN 8500). The GBM on-ground location is consistent with the Swift position. The GBM light curve shows a single peak with a duration (T90) of about 45 s (8-1000 keV). The time-averaged spectrum from T0-6.144 s to T0+26.624 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -1.28 +/- 0.09 and the cutoff energy, parameterized as Epeak is 240 +/- 60 keV. (chi squared 510 for 478 d.o.f.) The event fluence (8-1000 keV) in this time interval is (6.53 +/- 0.43)E-06 erg/cm^2. The 1-sec photon flux measured starting from T0+9.216 s in the 8-1000 keV band is 3.2 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."