TITLE: GCN CIRCULAR NUMBER: 27423 SUBJECT: GRB 200323A: Fermi GBM detection DATE: 20/03/23 22:23:15 GMT FROM: Peter Veres at UAH P. Veres and C. Meegan (both UAH) report on behalf of the Fermi GBM Team: "At 18:46:32.96 UT on 23 March 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200323A (trigger 606681997 / 200323782). The location for this GRB was reported in the Fermi GBM Final Real-time Localization GCN (GCN 27422). The angle from the Fermi LAT boresight at the GBM trigger time is 18 degrees. The GBM light curve consists of of a single pulse with a duration (T90) of about 2.1 s (50-300 keV). The time-averaged spectrum from T0 to T0+3.6 s is best fit by a Band function with Epeak = 63.0 +/- 3.7 keV, alpha = -0.73 +/- 0.10, and beta = -2.50 +/- 0.09. The event fluence (10-1000 keV) in this time interval is (3.23 +/- 0.10)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.32 s in the 10-1000 keV band is 25.60 +/- 0.44 ph/s/cm^2. The 64 ms peak photon flux measured starting from T0+0.58 s in the same band is 34.0 +/- 1.9 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/"