GCN Circular 27266
E. Bissaldi (Politecnico and INFN Bari), C. Meegan (UAH), and J. Wood (NASA/MSFC) report on behalf of the Fermi GBM Team: "At 11:14:43.89 UT on 28 February 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200228B (trigger 604581288 / 200228469), which was also detected by the Swift/BAT (Laha et al. 2020, GCN 27254). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 59 degrees. The GBM light curve shows a single emission episode with a duration (T90) of about 14 s (50-300 keV). The time-averaged spectrum from T0-4 s to T0+11 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -1.17 +/- 0.33 and the cutoff energy, parameterized as Epeak, is 76 +/- 16 keV. The event fluence (10-1000 keV) in this time interval is (1.30 +/- 0.18)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.3 s in the 10-1000 keV band is 1.4 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"