GCN Circular 9130
Rob Preece (UAH)reports on behalf of the Fermi GBM Team: "At 20:06:36.89 UT on 4 April, 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090411 (trigger 261173198 / 090411838). The on-ground calculated location, using the GBM trigger data, is RA = 159.34, DEC = -68.36 (J2000 degrees, equivalent to 10 h 37 m, 68 d 21'), with an uncertainty of 2.3 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 59 degrees. The GBM light curve consists of two main pulses with a duration (T90) of about 24.6 s (8-1000 keV). The time-averaged spectrum from T0-2.04 s to T0+18.4 s is best fit by a Band function with Epeak = 141 +/- 35 keV, alpha = -0.88 +/- 0.15, and beta = -1.82 +/- 0.08 (chi squared 319.93 for 318 d.o.f.). The event fluence (8-1000 keV) in this time interval is (8.6 +/- 1.2)E-6 erg/cm^2. The 0.256-sec peak photon flux measured starting from T0+11.75 s in the 8-1000 keV band is 3.25 +/- 0.94 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."