//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19111 SUBJECT: GRB 160227B: Fermi GBM detection DATE: 16/02/28 20:58:28 GMT FROM: Matthew Stanbro at UAH/Fermi Matthew Stanbro (UAH) and C. Meegan (UAH) reports on behalf of the Fermi GBM Team: "At 19:57:06.33 UT on 27 February 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160227B (trigger 478295830 / 160227831). The on-ground calculated location, using the GBM trigger data, is RA = 123.4, DEC = -48.3, with an uncertainty of 1.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ). The angle from the Fermi LAT boresight at the GBM trigger time is 54 degrees. The GBM light curve consists of 2 episodes with a duration (T90) of about 8 s (50-300 keV). The time-averaged spectrum from T0+0.14 s to T0+8.34 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.25 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 544 +/- 19 keV The event fluence (10-1000 keV) in this time interval is (1.86 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.73 s in the 10-1000 keV band is 10.27 +/- 0.27 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."