TITLE: GCN CIRCULAR NUMBER: 41662 SUBJECT: GRB 250902A: Fermi GBM Detection DATE: 25/09/02 19:12:27 GMT FROM: sumanbala2210@gmail.com S. Bala (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 01:30:00.49 UT on 02 September 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250902A (trigger 778469405/250902062). The Fermi-GBM position was reported in GCN 41648 (Fermi GBM Team 2025). The angle from the Fermi LAT boresight is 78 degrees. The GBM light curve consists of a bright pulse with a duration (T90) of about 8.4 s (50-300 keV). The time-averaged spectrum from T0-1.0 to T0+17.4 s is best fit by Band function with a Band function with Epeak = 257 +/- 13 keV, alpha = -1.25 +/- 0.02, and beta = -2.31 +/- 0.1. A power law function with an exponential high-energy cutoff fits the spectrum equally well with a with power law index = -1.28 +/- 0.01 and Epeak = 294 +/- 10 keV. The event fluence (10-1000 keV) in this time interval is (3.06 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.5 s in the 10-1000 keV band is 43.5 +/- 0.5 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/41662. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...