TITLE:   GCN CIRCULAR
NUMBER:  45766
SUBJECT: GRB 260926C: Fermi GBM Final Real-time Localization
DATE:    26/09/26 23:37:41 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 23:27:12 UT on 26 Sep 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260926C (trigger 812158037.168668 / 260926977).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 313.8, Dec = 10.1 (J2000 degrees, equivalent to J2000 20h 55m, 10d 05'), with a statistical uncertainty of 5.3 degrees.

The angle from the Fermi LAT boresight is 46.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260926977/quicklook/glg_skymap_all_bn260926977.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/bn260926977/quicklook/glg_healpix_all_bn260926977.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260926977/quicklook/glg_lc_medres34_bn260926977.gif