TITLE: GCN CIRCULAR NUMBER: 10868 SUBJECT: GRB 100619A: Fermi GBM detection DATE: 10/06/20 14:52:19 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAH) reports on behalf of the Fermi GBM Team: "At 03:55:23.71 UT on 19 June 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100619A (trigger 298612525 / 100619015). which was also detected by the SWIFT-BAT (Cannizzo et al. 2008, GCN 10863) The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 117 degrees. The GBM light curve shows 2 well separated pulses with a duration (T90) of about 96.8 s (50-300 keV). The time-averaged spectrum from T0-9.216 s to T0+101.378 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -1.61 +/- 0.05 and the cutoff energy, parameterized as Epeak, is 143.2 +/- 24.8 keV (C-stat 419 for 241 d.o.f.). The event fluence (8-1000 keV) in this time interval is (1.71 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+83 s in the 10-1000 keV band is 1.88 +/- 0.04 ph/s/cm^2. A Band function fits the spectrum equally well (C-stat 419 for 240 d.o.f.) with Epeak= 135.3 +/- 37.1 keV, alpha = -1.60 +/- 0.07 and beta = -2.36 +/- 0.69. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."