TITLE: GCN CIRCULAR NUMBER: 22100 SUBJECT: GRB 171103A: Fermi GBM observation DATE: 17/11/05 16:12:21 GMT FROM: Peter Veres at UAH P Veres (UAH) reports on behalf of the Fermi GBM Team: " GRB 171103A, detected by Swift (Ukwatta et al, GCN #22095) is clearly visible in the GBM data. It was not possible for GBM to trigger at this time because GBM was still in trigger mode for a transient that occurred 190 s earlier (171103963 / 531443246). The angle from the Fermi LAT boresight at the Swift trigger time is 102 degrees. The GBM light curve shows a single pulse with a duration (T90) of about 1.1 s (50-300 keV). The time-averaged spectrum for a 0.4 s interval starting from 23:10:31.951 UT is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.74 +/- 0.05 and the cutoff energy, parameterized as Epeak, is 2.1 +/- 0.2 MeV. The event fluence (10-1000 keV) in this time interval is (2.7 +/- 0.1)E-6 erg/cm^2. The 64-ms peak photon flux measured starting from 23:10:32.082 in the 10-1000 keV band is 30.3 +/- 2.0 ph/s/cm^2. "