GCN Circular 9413
Sheila McBreen (UCD/MPE) reports on behalf of the Fermi GBM Team: "At 03:17:20.17 UT on 16 May 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090516B (trigger 264136642 / 090516137). The on-ground calculated location, using the GBM trigger data, is RA = 122.2, DEC = -71.62 (J2000 degrees, equivalent to 08 h 09 m, -71 d 37 '), with an uncertainty of 2.6 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 45 degrees. The GBM light curve consists of several overlapping peaks from the trigger to about 140 s and possible weak emission out to about 350 s. The time-averaged spectrum from T0 s to T0+138 s is adequately fit by a power law function with an exponential high energy cutoff. The power law index is -1.01 (+/-0.06) and the cutoff energy, parameterized as Epeak, is 327.0 (+/-58.7) keV (chi squared 419 for 359 d.o.f.). The event fluence (8-1000 keV) in this time interval is (3.0 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+80 s in the 8-1000 keV band is 4.0 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."