TITLE:   GCN CIRCULAR
NUMBER:  44425
SUBJECT: GRB 260429A: Fermi GBM Final Real-time Localization
DATE:    26/04/29 23:34:38 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 23:24:02 UT on 29 Apr 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260429A (trigger 799197847.01658 / 260429975).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 283.9, Dec = 18.1 (J2000 degrees, equivalent to J2000 18h 55m, 18d 06'), with a statistical uncertainty of 2.6 degrees.

The angle from the Fermi LAT boresight is 76.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260429975/quicklook/glg_skymap_all_bn260429975.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/bn260429975/quicklook/glg_healpix_all_bn260429975.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260429975/quicklook/glg_lc_medres34_bn260429975.gif