TITLE: GCN CIRCULAR NUMBER: 41933 SUBJECT: GRB 250921A: Fermi GBM Final Localization DATE: 25/09/22 04:52:19 GMT FROM: rhamburg@usra.edu The Fermi GBM team reports the detection of a likely LONG GRB "At 03:07:21.46 UT on 22 September 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250921A (trigger 780203246/250922130). 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 = 353.54, Dec = 0.42 (J2000 degrees, equivalent to J2000 23h 34m, +0d 25'), with a statistical uncertainty of 6.13 degrees. The angle from the Fermi LAT boresight is 86 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250922130/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/bn250922130/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250922130/q..." View this GCN Circular online at https://gcn.nasa.gov/circulars/41933. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...