TITLE: GCN CIRCULAR NUMBER: 20156 SUBJECT: GRB 161109A: Fermi GBM observation DATE: 16/11/09 15:45:37 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (Politecnico & INFN Bari) reports on behalf of the Fermi GBM Team: "At 06:18:45.66 UT on 9 November 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 161109A (trigger 50036512 / 161109263), which was also detected by the Fermi/LAT (Desiante et al. 2008, GCN 20155). The GBM on-ground location is consistent with the LAT position. The angle from the Fermi LAT boresight at the GBM trigger time is 77 degrees. The GBM light curve consists of three peaks with a duration (T90) of about 24 s (50-300 keV). The time-averaged spectrum from T0 to T0+30 s is best fit by a Band function with Epeak = 250 +/- 16 keV, alpha = -0.73 +/- 0.04, and beta = -2.06 +/- 0.06. The event fluence (10-1000 keV) in this time interval is (2.30 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+17 s in the 10-1000 keV band is 16.7 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."