TITLE: GCN CIRCULAR NUMBER: 41169 SUBJECT: GRB 250725A: Fermi GBM Observation DATE: 25/07/25 17:08:33 GMT FROM: Matt Godwin <msg0028@uah.edu> Matt Godwin (UAH), R. Sonawane (IISER TVM) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 01:51:34.81 UT on 25 July 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250725A (trigger 775101099/250725077). which was also detected by Swift XRT (Evans et al. 2025, GCN 41152), Konus-Wind (Frederiks et al. 2025, GCN 41166), and Fermi LAT (Airasca et al. 2025, GCN 41161). The Fermi GBM on-ground location is consistent with the Swift XRT position. The redshift observed by VLT (Thakur et al. 2025, GCN 41160) is z = 5.26. The angle from the Fermi LAT boresight is 24 degrees. The GBM light curve consists of one main peak and a weaker secondary peak with a duration (T90) of about 9.5 s (50-300 keV). The time-averaged spectrum from T0+0.003 to T0+11.904 s is best fit by a Band function with Epeak = 161 +/- 7 keV, alpha = -0.47 +/- 0.05, and beta = -2.7 +/- 0.2. The event fluence (10-1000 keV) in this time interval is (1.18 +/- 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 18 +/- 0.4 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/" View this GCN Circular online at https://gcn.nasa.gov/circulars/41169. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...