TITLE: GCN CIRCULAR NUMBER: 44747 SUBJECT: GRB 260531B: Fermi GBM Final Real-time Localization DATE: 26/05/31 14:08:37 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 13:57:59 UT on 31 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260531B (trigger 801928684.989378 / 260531582). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 282.6, Dec = 6.4 (J2000 degrees, equivalent to J2000 18h 50m, 6d 24'), with a statistical uncertainty of 2.2 degrees. The angle from the Fermi LAT boresight is 48.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260531582/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/bn260531582/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260531582/q... View this GCN Circular online at https://gcn.nasa.gov/circulars/44747. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...