TITLE: GCN CIRCULAR NUMBER: 43146 SUBJECT: GRB 251217A: Fermi GBM Final Real-time Localization DATE: 25/12/17 04:46:13 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 04:35:34 UT on 17 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251217A (trigger 787638939.89203 / 251217191). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 325.8, Dec = 20.9 (J2000 degrees, equivalent to J2000 21h 43m, 20d 53'), with a statistical uncertainty of 6.6 degrees. The angle from the Fermi LAT boresight is 29.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251217191/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/bn251217191/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251217191/q... View this GCN Circular online at https://gcn.nasa.gov/circulars/43146. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...