GCN Circular 8921
S. Guiriec (UAH) reports on behalf of the Fermi GBM Team: "At 18:31:01.41 UT on 27 February 2009, the Fermi Gamma-Ray Burst Monitor triggered and located the short and bright GRB 090227B (trigger 257452263 / 090227772). The on-ground calculated location, using the GBM trigger data, is RA = 11.81, Dec = +32.17 (J2000 degrees, equivalent to 11h48m36,+32d10'12), with an uncertainty of 1.77 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 72 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of one spike with a duration (T90) of about 0.9 s (10-1000 keV). The time-averaged spectrum from T0-0.1s to T0+0.4s is best fitted by a Band function with Epeak = 2255 +/- 116 keV, alpha = -0.53 +/- 0.02, and beta = -3.04 +/- 0.23 (chi squared 673 for 607 d.o.f.). The event fluence (10-1000 keV) in this time interval is (0.87 +/- 0.01)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0 in the 10-1000 keV band is 34.6 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."