GCN Circular 34886
J.Mangan (CNRS/IJCLab) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 06:46:59.59 UT on 25 October 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231025A (trigger 719909224/231025283). which was also detected by Swift/BAT-GUANO (Ronchini et al. 2023, GCN 34884). The Fermi GBM Final Real-time Localization is reported in GCN 34883. The GBM light curve consists of a single emission episode with a duration (T90) of about 6 s (50-300 keV). The time-averaged spectrum from T0-2.0 to T0+4.1 s is best fit by a simple power law function with index -1.4 +/- 0.1. 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 T0-3.1 s in the 10-1000 keV band is 1.3 +/- 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/"