TITLE: GCN CIRCULAR NUMBER: 40864 SUBJECT: GRB 250628C: Fermi GBM Final Real-time Localization DATE: 25/06/28 19:25:46 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 19:15:16 UT on 28 Jun 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250628C (trigger 772830921.339792 / 250628802).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 169.9, Dec = -6.9 (J2000 degrees, equivalent to J2000 11h 19m, -6d 54'), with a statistical uncertainty of 3.7 degrees.

The angle from the Fermi LAT boresight is 11.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250628802/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/bn250628802/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250628802/q...

View this GCN Circular online at https://gcn.nasa.gov/circulars/40864. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...