TITLE:   GCN CIRCULAR
NUMBER:  45053
SUBJECT: GRB 260628A: Fermi GBM Final Real-time Localization
DATE:    26/06/28 22:03:44 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 SHORT GRB

At 21:51:24 UT on 28 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260628A (trigger 804376289.020238 / 260628911).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 308.2, Dec = -6.9 (J2000 degrees, equivalent to J2000 20h 32m, -6d 54'), with a statistical uncertainty of 14.3 degrees.

The angle from the Fermi LAT boresight is 63.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260628911/quicklook/glg_skymap_all_bn260628911.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260628911/quicklook/glg_healpix_all_bn260628911.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260628911/quicklook/glg_lc_medres34_bn260628911.gif