GCN Circular 23385
P. Veres (UAH) and E. Bissaldi (Politecnico & INFN Bari) report on behalf of the Fermi GBM Team: "At 01:49:47.31 UT on 27 October 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 181027A (trigger 56229779 / 181027076), which was also detected by the Swift/BAT (Lien et al. 2018, GCN 23383). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 61 degrees. The GBM light curve consists of two pulses with a duration (T90) of about 90 s (50-300 keV). The time-averaged spectrum from T0-84.5 s to T0+44.5 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.10 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 183 +/- 27 keV. The event fluence (10-1000 keV) in this time interval is (7.76 +/- 0.57)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.64 s in the 10-1000 keV band is 2.48 +/- 0.22 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."