TITLE: GCN CIRCULAR NUMBER: 16658 SUBJECT: GRB 140801A: Fermi GBM observation DATE: 14/08/02 05:37:24 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) reports on behalf of the Fermi GBM Team: "At 18:59:53.26 UT on 1 August 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140801A (trigger 428612396 / 140801792). An optical transient was detected by the MASTER II robotic telescope (Lipunov et al. 2014, GCN 16653). The GBM on-ground location is consistent with the OT location, which angle from the Fermi LAT boresight is 80 degrees. The GBM light curve consists of two bright pulses followed by a short tail, with a duration (T90) of about 7 s (50-300 keV). The time-averaged spectrum from T0-2.048 s to T0+12.288 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.42 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 125 +/- 2 keV (Castor-statistics 697.99 for 610 d.o.f.). A Band function fits the spectrum equally well (Castor-statistics 695.14 for 609 d.o.f.) with Epeak= 122 +/- 3 keV, alpha = -0.40 +/- 0.04 and beta = -3.6 +/- 0.4. The event fluence (10-1000 keV) in this time interval is (1.22 +/- 0.01)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+0.832 s in the 10-1000 keV band is 22.6 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."