TITLE: GCN CIRCULAR NUMBER: 9560 SUBJECT: GRB 090621D: Fermi GBM detection DATE: 09/06/22 19:47:45 GMT FROM: Arne Rau at MPE Arne Rau (MPE) reports on behalf of the Fermi GBM Team: "At 10:43:45.14 UT on 21 June 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090621D (267273827 / 090621447). The on-ground calculated location, using the GBM trigger data, is RA = 12.3, DEC = -22.6 (J2000 degrees, equivalent to 00 h 49 m, -22 d 36 '), with an uncertainty of 4.9 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 79 degrees. The GBM light curve consists of two peaks with a duration (T90) of about 39.9 s (8-1000 keV). The time-averaged spectrum from T0-1.024 s to T0+20.480 s is adequately fit by a simple power law function with index -1.66 +/- 0.05 (chi squared 752 for 694 d.o.f.). The event fluence (8-1000 keV) in this time interval is (1.34 +/- 0.03)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0-1.024 s in the 8-1000 keV band is 1.74 +/- 0.05 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."