TITLE:   GCN CIRCULAR
NUMBER:  45464
SUBJECT: GRB 260829A: Fermi GBM Final Real-time Localization
DATE:    26/08/29 06:18:41 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 06:08:09 UT on 29 Aug 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260829A (trigger 809676494.389126 / 260829256).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 242.3, Dec = -34.6 (J2000 degrees, equivalent to J2000 16h 09m, -34d 36'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 47.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260829256/quicklook/glg_skymap_all_bn260829256.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/bn260829256/quicklook/glg_healpix_all_bn260829256.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260829256/quicklook/glg_lc_medres34_bn260829256.gif