TITLE: GCN CIRCULAR NUMBER: 8589 SUBJECT: GRB 081126: Fermi GBM detection DATE: 08/12/01 17:28:29 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAH) and A.J. van der Horst (NASA/ORAU) report on behalf of the Fermi GBM Team: "At 21:34:09.06 UT on 26th November 2008, the Fermi Gamma-Ray Burst Monitor triggered and located GRB081126 (trigger 249428050 / 081126899) which was also detected by the SWIFT-BAT (Margutti et al. 2008, GCN Circular 8554) The angle from the Fermi LAT boresight is 18 degrees. This burst was also independently detected by INTEGRAL SPI-ACS and Konus/Wind (Golenetskii et al., 2008, GCN Circular 8562). The GBM light curve consists of two pulses separated by about 30 s with almost no emission in between. There is also a weak untriggered emission at about T0-20 s. The burst duration (T90) is about 56 s (8-1000 keV). The time-averaged spectrum of the first pulse from T0 s to T0+11 s is well fit by a Band function with Epeak = 192 +/- 74 keV, alpha = -0.3 +/- 0.4, and beta = -1.6 +/- 0.1.(chi squared 547 for 487 d.o.f.) Similarly the second pulse from about 20 s to 40 s is also well fit by a Band function with Epeak = 162 +/- 77 keV, alpha = -0.3 +/- 0.5, and beta = -1.6 +/- 0.1. (chi squared 539 for 487 d.o.f.). The time averaged spectrum of the entire burst is well fit by a Band function with Epeak = 176 +/- 84 keV, alpha = -0.3 +/- 0.5, and beta = -1.7 +/- 0.1. (chi squared 464 for 487 d.o.f.) The event fluences (8-1000 keV) in the two pulses are (2.7 +/- 0.8)E-07 erg/cm^2 and (1.9 +/- 0.8)E-07 erg/cm^2 respectively. The 1-sec peak photon fluxes in the 8-1000 keV band in the two pulses are 1.3+/- 0.4 ph/s/cm^2 and 1.0 +/- 0.4 ph/s/cm^2 respectively. The total event fluence (8-1000 keV) is (1.5 +/- 0.6)E-07 erg/cm^2. The 1-sec peak photon fluxes in the 8-1000 keV band in the two pulses are 0.7+/- 0.3 ph/s/cm^2 The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."