"At 03:21:01.93 UT on 31 December 2008, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 081231 (trigger 252386462 / 081231140).

The on-ground calculated location, using the GBM trigger data, is RA = 218.74, DEC = -38.72 (J2000 degrees, equivalent to 14 h 35 m, -38 d 43'), with an uncertainty of 1.0 degree (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 Fermi LAT boresight is 20 degrees. This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of three main emission peaks with apparent substructure and a duration (T90) of about 29 s (8-1000 keV). The time-averaged spectrum from T0-4.1 s to T0+37.9 s is best fit by a Band function with Epeak = 152.3 +/- 11.9 keV, alpha = -0.80 +/- 0.06, and beta = -2.03 +/- 0.07. (chi squared 998 for 726 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 1.2E-05 +/- 5.9E-07 erg/cm^2. The peak photon flux measured starting from T0-4.1 s in the 8-1000 keV band is 1.53 +/- 0.08 ph/s/cm^2.

The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."