TITLE: GCN CIRCULAR NUMBER: 17364 SUBJECT: GRB 150127B: Fermi GBM detection DATE: 15/01/30 17:36:16 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team: "At 14:08:26.68 UT on January 27 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150127B (trigger 444060509/150127589). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with the IPN Triangulation (K. Hurley et al., GCN 17360). This burst was also observed by Konus-Wind (S. Golenetskii et al., GCN 17363). The angle of the burst direction to the Fermi LAT boresight is 80 degrees. The GBM light curve consists of two peaks with a duration (T90) of about 61 s (50-300 keV). The time-averaged spectrum from T0+0.0 s to T0+79 s is adequately fit by a Band function with Epeak = 240 +/- 7 keV, Alpha =-1.08 +/- 0.01 and Beta = -2.8 +/- 0.2. The spectrum is also well fit by a power law function with an exponential high-energy cutoff. The power law index is -1.09 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 250 +/- 5 keV. The event fluence (10-1000 keV) in this time interval is (1.99 +/- 0.01)E-05 erg/cm^2. The 1 s peak photon flux measured starting from T0+55 s in the 10-1000 keV band is 19.8 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."