TITLE: GCN CIRCULAR NUMBER: 17355 SUBJECT: GRB150127A: Fermi GBM Detection DATE: 15/01/28 00:46:25 GMT FROM: Matthew Stanbro at UAH/Fermi Matthew Stanbro (UAH) and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team: "At 09:32:44.14 UT on 27 January 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150127A (trigger 444043967 / 150127398). The on-ground calculated location, using the GBM trigger data, is RA = 285.7, DEC = -8.4, with an uncertainty of 2.8 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 39 degrees. The GBM light curve consists of several episodes with a duration (T90) of about 53 s (50-300 keV). The time-averaged spectrum from T0-0.00 s to T0+51.20 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.04 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 1478 +/- 225 keV. A Band function fits the spectrum equally well with Epeak= 1083 +/- 212 keV, alpha = -0.99 +/- 0.05 and beta = -2.21 +/- 0.23. The event fluence (10-1000 keV) in this time interval is (2.27 +/- 0.50)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.32 s in the 10-1000 keV band is 7.78 +/- 0.33 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."