TITLE: GCN CIRCULAR NUMBER: 19006 SUBJECT: GRB 160206B: Fermi GBM detection DATE: 16/02/09 17:07:58 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 10:19:12.43 UT on 06 February 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160206B (trigger 476446756 / 160206430). A list of optical candidates were observed by iPTF within the 2-sigma statistical+systematic region of the final on-ground calculated location (Singer et al., GCN 18995). The on-ground calculated location, using the GBM trigger data, is RA = 184.3, DEC = 52.4 (J2000 degrees, equivalent to 12h 17m, 52d 24'), with an uncertainty of 4.2 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 is about 83 degrees. The GBM light curve consists of a FRED-like pulse with a duration (T90) of about 21.5 s (50-300 keV). The time-averaged spectrum from T0-4.9 s to T0+16.6 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.93 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 356.0 +/- 69.5 keV. The event fluence (10-1000 keV) in this time interval is (4.6 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+3.4 s in the 10-1000 keV band is 3.0 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."