GCN Circular 9932
E.Bissaldi and D.Gruber (all MPE) report on behalf of the Fermi GBM Team: "At 09:20:33.67 UT on 25 September 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090925 (trigger 275563235 / 090925389). The on-ground calculated location, using the GBM trigger data, is RA = 333.2, DEC = +14.3 (J2000 degrees, equivalent to 22h 13m, 14d 18'), with an uncertainty of 4.5 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 116 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of a FRED-like pulse with a duration (T90) of about 50 s (8-1000 keV). The time-averaged spectrum from T0-1 s to T0+20 s is adequately fit by a Band function with Epeak = 156 (+25/-20) keV, alpha = -0.60 (+0.14/-0.13), and beta = -1.91 (+0.07/-0.09) (C-stat 369 for 357 d.o.f.). The event fluence (8-1000 keV) in this time interval is (9.46 +/- 0.26)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6 s in the 8-1000 keV band is 4.2 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."