GCN Circular 8664
Colleen A. Wilson-Hodge (NASA/MSFC) and Valerie Connaughton (UAH) report on behalf of the Fermi GBM Team: "At 23:41:56.39 UT on 9 December 2008, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 081209 (trigger 250558317 / 081209981). The on-ground calculated location, using the GBM trigger data, is RA = 45.3, DEC = 63.5 (J2000 degrees, equivalent to 02 h 20 m, 68 d 52'), with an uncertainty of 4.9 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location overlaps the IPN arc reported in Golenetskii et al. 2008 (GCN Circular #8646). The angle from the Fermi LAT boresight is 109 degrees. The GBM light curve consists of a single peak with a duration (T90) of about 0.4 s (8-1000 keV). The time-averaged spectrum from T0-0.110 s to T0+0.210 s is best fit by a Band function with Epeak = 808 +/- 163 keV, alpha = -0.5 +/- 0.1, and beta = -2.0 +/- 0.1. (chi squared 321.85 for 360 d.o.f.). The event fluence (8-1000 keV) in this time interval is (5.9 +/- 0.3)E-07 erg/cm^2. The 1-sec photon flux measured starting from T0-0.110 s in the 8-1000 keV band is 7.8 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."