TITLE: GCN CIRCULAR NUMBER: 17001 SUBJECT: GRB 141031A: Fermi GBM detection DATE: 14/10/31 16:44:12 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "At 07:18:21.67 UT on the 31st of October 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141031A (trigger 436432704 / 141031304), which was also detected by Swift (Gompertz et al. 2014, GCN 16995). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with the Swift location. The angle from the Fermi LAT boresight is about 34 degrees. The GBM light curve consists of a single peak with a duration (T90) of about 19.4 s (50-300 keV). The time-averaged spectrum from T0-6.1 s to T0+13.3 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -1.09 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 410 +/- 66 keV. A Band function fits the spectrum equally well with Epeak = 221 (+/-57) keV, alpha = -0.92 +/- 0.12 , and beta = -1.76 (+/-0.09). The event fluence (10-1000 keV) in this time interval is (5.7 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.8 s in the 10-1000 keV band is 2.7 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." ________________________________