TITLE: GCN CIRCULAR NUMBER: 41918 SUBJECT: GRB 250920A: Fermi GBM Detection DATE: 25/09/20 21:01:18 GMT FROM: Rushikesh Digambar Sonawane PHD231014 at IISER, TVM <rushikesh23@iisertvm.ac.in> R. Sonawane (IISER, TVM) and J.R. Smith (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 02:54:06.82 UT on 20 September 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250920A (trigger 780029651/250920121). which was also detected by AstroSat-CZTI( Harsha K. H. et al. 2025, GCN 41899), and SVOM-GRM (Chen-Wei Wang et al. 2025, GCN 41912). The Fermi GBM Final Localization is presented in GCN 41895. The angle from the Fermi LAT boresight is 88 degrees. The GBM light curve consists of two emission episodes with a duration (T90) of about 9.4 s (50-300 keV). The time-averaged spectrum from T0+0.003 to T0+13.312 s is best fit by a Band function with Epeak = 151 +/- 3 keV, alpha = -0.81 +/- 0.02, and beta = -2.39 +/- 0.04. The event fluence (10-1000 keV) in this time interval is (4.22 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.7 s in the 10-1000 keV band is 102.5 +/- 0.7 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/41918. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...