TITLE: GCN CIRCULAR NUMBER: 41753 SUBJECT: GRB 250909A: Fermi GBM Final Real-time Localization DATE: 25/09/09 02:43:59 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 02:33:28 UT on 9 Sep 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250909A (trigger 779078013.882702 / 250909107). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 78.8, Dec = 39.5 (J2000 degrees, equivalent to J2000 05h 15m, 39d 30'), with a statistical uncertainty of 3.3 degrees. The angle from the Fermi LAT boresight is 85.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250909107/q... The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250909107/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250909107/q... View this GCN Circular online at https://gcn.nasa.gov/circulars/41753. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...