GCN Circular 31760
R. Hamburg (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 16:33:18.40 UT on 11 March 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 220311A (trigger 668709203 / 220311690), which was also detected by the INTEGRAL/IBAS (Mereghetti et al. 2022, GCN 31740). The Fermi GBM Final Real-time Localization (GCN 31744) is largely consistent with the INTEGRAL position. The angle from the Fermi LAT boresight at the GBM trigger time is 111 degrees. The GBM light curve shows a single spike with a duration (T90) of about 10 s (50-300 keV). The time-averaged spectrum from T0-5.1 s to T0+0.0 s is adequately a simple power law function with index -1.55 +/- 0.11. The event fluence (10-1000 keV) in this time interval is (1.8 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-4.7 s in the 10-1000 keV band is 1.8 +/- 0.3 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/"