TITLE: GCN CIRCULAR NUMBER: 21980 SUBJECT: GRB 171007A: Fermi GBM observation DATE: 17/10/07 22:45:12 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP Elisabetta Bissaldi (Politecnico & INFN Bari) reports on behalf of the Fermi GBM Team: "At 11:57:39.90 UT on 07 October 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 171007A (trigger 529070264 / 171007498), which was also detected by the Swift-BAT (Cannizzo et al. 2017, GCN 21976). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 50 degrees. The GBM light curve consists of single peak with a duration (T90) of about 3.5 s (50-300 keV). The time-averaged spectrum from T0-1.4 s to T0+2.1 s is adequately fit by a simple power law function with index -1.31 +/- 0.07. The event fluence (10-1000 keV) in this time interval is (6.1 +/- 0.7)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-1 s in the 10-1000 keV band is 1.5 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."