TITLE: GCN CIRCULAR NUMBER: 42596 SUBJECT: GRB 251105A: Fermi GBM Observation DATE: 25/11/05 23:37:24 GMT FROM: oindabimukherjee@gmail.com O. Mukherjee (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 04:41:06.40 UT on 05 November 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251105A (trigger 784010471/251105195) which was also detected by Swift/BAT-GUANO (J. DeLaunay et al. 2025, GCN 42593). The Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position. The angle from the Fermi LAT boresight is 41 degrees. The GBM light curve consists of one emission episode with a duration (T90) of about 65 s (50-300 keV). The time-averaged spectrum from T0-23 to T0+87 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.13 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 220 +/- 30 keV. A Band function fits the spectrum equally well with Epeak= 190 +/- 30 keV, alpha = -1.08 +/- 0.08 and beta = -2.38 +/- 0.39. The event fluence (10-1000 keV) in this time interval is (1.26 +/- 0.07)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+8.8 s in the 10-1000 keV band is 3.2 +/- 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/" View this GCN Circular online at https://gcn.nasa.gov/circulars/42596. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...