TITLE: GCN CIRCULAR NUMBER: 9562 SUBJECT: GRB 090621B: Fermi GBM detection DATE: 09/06/23 00:03:11 GMT FROM: Adam Goldstein at Fermi-GBM/UAH A. Goldstein (UAH) and J.M. Burgess (UAH) report on behalf of the Fermi GBM Team: "At 22:07:25.70 UT on 21 June 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090621B (trigger 267314847 / 090621922) which was also detected by the Swift BAT (P.A. Curran et al. 2009, GCN 9545). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 108 degrees. The GBM light curve consists of one short spike with a duration (T90) of about 0.128 s (8-1000 keV). The time-averaged spectrum from T0-0.064 s to T0+0.064 s is best fit by a Band function with Epeak = 321.60 +/- 129.00 keV, alpha = -0.13 +/- 0.38, and beta = -1.57 +/- 0.08 (chi squared 401 for 481 d.o.f.). The event fluence (8-1000 keV) in this time interval is (3.71 +/- 0.58)E-07 erg/cm^2. The 0.128-sec peak photon flux measured starting from T0-0.064 s in the 8-1000 keV band is 6.4 +/- 1.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."