TITLE: GCN CIRCULAR NUMBER: 15599 SUBJECT: GRB 131216A: Fermi GBM observation DATE: 13/12/17 01:59:46 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) reports on behalf of the Fermi GBM Team: "At 01:56:32.06 UT on 16 December 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 131216A (trigger 408851795 / 131216081). It was also detected by the Fermi Large Area Telescope (Veres et al 2013, GCN 15598). The on-ground calculated location, using the GBM trigger data, is RA = 91.6, DEC = -35.5 (J2000 degrees, equivalent to +06h 06m, -35d 30'), with an uncertainty of 2.7 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 was 44 degrees at trigger time, then an autonomous repoint maneuver placed the GRB near the center of the LAT field-of-view. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of a single FRED pulse with a duration (T90) of about 24 s (50-300 keV). The time-averaged spectrum from T0-0.256 s to T0+11.264 s, when the flux is highest, is best fit by a Band function with Epeak = 359 +/- 40 keV, alpha = -0.64 +/- 0.07, and beta = -2.03 +/- 0.13 (Castor statistics 777.70 for 716 d.o.f.). The event fluence (10-1000 keV) in this time interval is (8.60 +/- 0.20)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+0.512 s in the 10-1000 keV band is 7.9 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."