TITLE: GCN CIRCULAR NUMBER: 43964 SUBJECT: GRB 260311B: Fermi GBM Final Real-time Localization DATE: 26/03/11 19:08:31 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 18:57:55 UT on 11 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260311B (trigger 794948280.422386 / 260311790). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 278.5, Dec = 0.4 (J2000 degrees, equivalent to J2000 18h 33m, 0d 24'), with a statistical uncertainty of 11.7 degrees. The angle from the Fermi LAT boresight is 54.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260311790/q... The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260311790/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260311790/q... View this GCN Circular online at https://gcn.nasa.gov/circulars/43964. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...