TITLE: GCN CIRCULAR NUMBER: 27543 SUBJECT: GRB 200411A: Fermi GBM observation DATE: 20/04/11 20:18:43 GMT FROM: Joshua Wood at MSFC/Fermi-GBM E. Bissaldi (Politecnico and INFN Bari), C. Meegan (UAH), and J. Wood (NASA/MSFC) report on behalf of the Fermi GBM Team: "At 04:29:02.52 UT on 11 April 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200411A (trigger 608272147 / 200411187), which was also detected by the Swift/BAT (Tohuvavohu et al. 2020, GCN 27536) The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 116 degrees. The GBM light curve shows a single pulse with a duration (T90) of about 1.4 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.192 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -0.64 +/- 0.22 and the cutoff energy, parameterized as Epeak, is 420 +/- 120 keV. The event fluence (10-1000 keV) in this time interval is (4.7 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0-0.064 s in the 10-1000 keV band is 11.9 +/- 1.5 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/"