TITLE: GCN CIRCULAR NUMBER: 44751 SUBJECT: GRB 260531C: Fermi GBM Final Localization Correction DATE: 26/05/31 23:57:21 GMT FROM: rhamburg@usra.edu The Fermi GBM team reports the detection of a likely SHORT GRB. "At 21:14:58.91 UT on 31 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260531C (trigger 801954903/260531885). This trigger was initially classified as Below Horizon by the flight software, but is in fact a GRB. The on-ground calculated location, using the Fermi GBM trigger data, is RA = 40.6, Dec = 36.2 (J2000 degrees, equivalent to J2000 2h 42m, +36d 12'), with a statistical uncertainty of 11.6 degrees. The angle from the Fermi LAT boresight is 82 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260531885/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/bn260531885/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260531885/q..." View this GCN Circular online at https://gcn.nasa.gov/circulars/44751. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...