TITLE: GCN CIRCULAR NUMBER: 8549 SUBJECT: GRB 081122: Fermi GBM detection DATE: 08/11/24 17:05:13 GMT FROM: Sheila McBreen at MPE Sheila McBreen (UCD/MPE) reports on behalf of the Fermi GBM Team: "At 12:28:12.21 UT on 22 November 2008, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 081122 (trigger 249049693 / 081122520). The on-ground calculated location, using the GBM trigger data, is RA = 338.7, DEC = +38.4 (J2000 degrees, equivalent to 22 h 35 m, +38 d 24 '), with an uncertainty of 1.2 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 21 degrees. This event generated an Autonomous Repoint Recommendation from GBM, which was accepted by the LAT and spacecraft. A 5 hour pointed mode observation was initiated at the location of this burst. The GBM light curve consists of 3 pulses with a duration (T90) of about 26 s (8-1000 keV). The time-averaged spectrum from T0-1 s to T0+26 s is adequately fit by a power law function with an exponential high energy cutoff. The power law index is -0.77 +/-0.07 and the cutoff energy, parameterized as Epeak, is 200.7 +/-15.7 keV (chi squared 431.7 for 353 d.o.f.). A Band function fits the spectrum equally well (chi squared 431.3 for 352 d.o.f.) with Epeak = 158.6 +/- 17.6 keV, alpha = -0.63 +/- 0.15 , and beta = -2.24 +/- 0.20. The event fluence (8-1000 keV) in this time interval is (9.6 +/- 1.1) E-6 erg/cm^2 (Band model). The 64 ms peak photon flux measured starting from T0+0.756 s in the 8-1000 keV band is 30.0 +/- 3.0 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."