TITLE: GCN CIRCULAR NUMBER: 43139 SUBJECT: GRB 251216A: Fermi GBM Final Real-time Localization DATE: 25/12/16 09:48:49 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 09:38:09 UT on 16 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251216A (trigger 787570694.65431 / 251216401). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 290.9, Dec = 52.0 (J2000 degrees, equivalent to J2000 19h 23m, 52d 00'), with a statistical uncertainty of 9.3 degrees. The angle from the Fermi LAT boresight is 42.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251216401/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/bn251216401/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251216401/q... View this GCN Circular online at https://gcn.nasa.gov/circulars/43139. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...