TITLE: GCN CIRCULAR NUMBER: 10912 SUBJECT: GRB 100625A: Fermi GBM detection DATE: 10/06/30 12:55:57 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAH) reports on behalf of the Fermi GBM Team: "At 18:32:28.47 UT on 25 June 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100625A (trigger 299183550 / 100625773). which was also detected by the SWIFT-BAT(Holland et al. 2008, GCN 10884) The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 125 degrees. The GBM light curve shows of 2 closely spaced narrow pulses with a duration (T90) of about 0.32 s (50-300 keV). The time-averaged spectrum from T0-0.128 s to T0+0.192 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -0.64 +0.12/-0.11 and the cutoff energy, parameterized as Epeak, is 509.2 +77.5/-61.5 keV (C-stat value 710 for 609 d.o.f.). The event fluence (8-1000 keV) in this time interval is (1.32 +/- 0.05)E-06 erg/cm^2. The 0.064-sec peak photon flux measured starting from T0-0.128 s in the 8-1000 keV band is 15.09 +/- 0.59 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."