TITLE: GCN CIRCULAR NUMBER: 10381 SUBJECT: GRB 100206A: Fermi GBM observation DATE: 10/02/06 19:02:46 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 13:30:05.39 UT on 06 February 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100206A (trigger 287155807 / 100206563) which was also detected by the SWIFT-BAT (Krimm et al. 2008, GCN 10376). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 44.7 degrees. The Fermi Observatory executed a maneuver following this trigger and tracked the burst location for the next 5 hours, subject to Earth-angle constraints. The GBM light curve shows a single bright peak with a duration (T90) of about 0.13 +/- 0.05 s (8-1000 keV). The time-averaged spectrum from T0-0.019 s to T0+0.109 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -0.18 (+/-0.13) and the cutoff energy, parameterized as Epeak, is 506 (+68/-53) keV (Castor C statistic of 569 for 479 d.o.f.) The event fluence (8-1000 keV) in this time interval is (9.3 +/- 0.4)E-07 erg/cm^2. The 0.016-sec peak photon flux measured starting from T0-0.003 s in the 8-1000 keV band is 31 +/- 2 ph/s/cm^2. A Band function fits the spectrum equally well (Castor C statistic of 565 for 478 d.o.f.) with Epeak= 439 (+73/-60) keV, alpha = -0.09 (+0.17/-0.15)and beta = -2.35 (+0.24/-0.43) . The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."