TITLE: GCN CIRCULAR NUMBER: 19064 SUBJECT: GRB 160223A: Fermi GBM observation DATE: 16/02/23 21:35:50 GMT FROM: Peter Veres at UAH P Veres (UAH), K Toelge (MPE), C Meegan (UAH) and C M Hui (MSFC) report on behalf of the Fermi GBM Team: "At 01:44:22.39 UT on 23 February 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160223A (trigger 477884666 / 160223072) which was also detected by the Swift/BAT (Markwardt et al., GCN 19057). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 75 degrees. The GBM light curve shows two separate peaks with a duration (T90) of about 117 s (50-300 keV). The time-averaged spectrum from T0-6 s to T0+124 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.96 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 308 +/- 30 keV. The event fluence (10-1000 keV) in this time interval is (1.46 +/- 0.06)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.7 s in the 10-1000 keV band is 5.4 +/- 0.2 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 282 +/- 45 keV, alpha = -0.94 +/- 0.08 and beta = -2.20 +/- 0.23. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."