GCN Circular 10546
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 06:36:08.02 UT on 25 March 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100325A (trigger 291191770/100325275). The on-ground calculated location, using the GBM trigger data, is RA = 332.3, DEC = -28.6 (J2000 degrees, equivalent to 22h 09m, -28d 36'), with an uncertainty of 1.5 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 9 degrees. The GBM light curve consists of a single structured pulse with a duration (T90) of 8.3 +/- 1.9 s (8-1000 keV). The time-averaged spectrum from T0-1.664 s to T0+7.552 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -0.45(+0.12/-0.11) and the cutoff energy, parameterized as Epeak, is 159.3 (+12.7/-10.8) keV (CSTAT 502 for 482 d.o.f). The event fluence (8-1000 keV) in this time interval is (1.99 +/- 0.04)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+0.512 s in the 8-1000 keV band is 5.0 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."