GCN Circular 31778
R. Hamburg (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 12:48:30.66 UT on 17 March 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 220317A (trigger 669214115 / 220317534). which was also detected by the Swift/BAT-GUANO (Tohuvavohu et al. 2022, GCN 31766). The angle from the Fermi LAT boresight at the GBM trigger time is 48 degrees. The GBM light curve shows two peaks with a duration (T90) of about 14 s (50-300 keV). The time-averaged spectrum from T0-6.1 s to T0+8.2 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.1 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 248 +/- 96 keV. The event fluence (10-1000 keV) in this time interval is (1.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+4.4 s in the 10-1000 keV band is 1.6 +/- 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/"