TITLE: GCN CIRCULAR NUMBER: 31011 SUBJECT: GRB 211024A: Fermi GBM detection DATE: 21/10/26 22:38:14 GMT FROM: Suraj Poolakkil at UAH <sp0076@uah.edu> S. Poolakkil (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 01:34:11.40 UT on 24 October 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 211024A (trigger 656732056 / 211024065) which was also detected by the Swift/BAT-GUANO (Tohuvavohu et al. 2021, GCN 31006). The GBM on-ground location is consistent with the Swift/BAT-GUANO position. The angle from the Fermi LAT boresight at the GBM trigger time is 119 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 0.06 s (50-300 keV). The time-averaged spectrum from T0-0.128 s to T0+0.128 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.23 +/- 0.39 and the cutoff energy, parameterized as Epeak, is 145 +/- 27 keV. The event fluence (10-1000 keV) in this time interval is (1.95 +/- 0.28)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0 s in the 10-1000 keV band is 10.4 +/- 1.4 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/"