TITLE: GCN CIRCULAR NUMBER: 8586 SUBJECT: GRB 081129: Fermi GBM detection DATE: 08/12/01 11:08:37 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 03:52:04.26 UT on 29 November 2008, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 081129 (trigger 249623525 / 081129161). The on-ground calculated location, using the GBM trigger data, is RA = 55.0, DEC = -63.0 (J2000 degrees, equivalent to 03h 40m, -63d 00'), with an uncertainty of 1.9 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 Fermi LAT boresight is 118 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve contains 2 peaks and has a duration (T90) of about 59 s (8-1000 keV) and (T50) of about 17 s (8-1000 keV). The time-averaged spectrum from T0+0.003 s to T0+59.521 s is best fit by a Band function with Epeak = 150 +/- 30 keV, alpha = -0.5 +/- 0.2, and beta = -1.84 +/- 0.08 (chi squared 253 for 233 d.o.f.). The event fluence (8-1000 keV) in this time interval is (2.0 +/- 0.3)E-05 erg/cm^2. The 1-sec photon flux measured starting from T0 s in the 8-1000 keV band is 14 +/- 3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."