TITLE: GCN CIRCULAR NUMBER: 40508 SUBJECT: GRB 250521A: Fermi GBM Final Real-time Localization DATE: 25/05/21 04:37:01 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 04:27:02 UT on 21 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250521A (trigger 769494427.113864 / 250521185). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 213.0, Dec = 30.1 (J2000 degrees, equivalent to J2000 14h 11m, 30d 06'), with a statistical uncertainty of 4.6 degrees. The angle from the Fermi LAT boresight is 74.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250521185/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/bn250521185/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250521185/q... View this GCN Circular online at https://gcn.nasa.gov/circulars/40508. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...