GCN Circular 44425
Subject
GRB 260429A: Fermi GBM Final Real-time Localization
Event
Date
2026-04-29T23:34:38Z (10 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
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