GCN Circular 43356
Subject
GRB 260109A: Fermi GBM Final Real-time Localization
Event
Date
2026-01-09T03:55:04Z (13 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 LONG GRB
At 03:44:24 UT on 9 Jan 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260109A (trigger 789623069.789512 / 260109156).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 307.3, Dec = -69.0 (J2000 degrees, equivalent to J2000 20h 29m, -69d 00'), with a statistical uncertainty of 8.0 degrees.
The angle from the Fermi LAT boresight is 90.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260109156/quicklook/glg_skymap_all_bn260109156.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/bn260109156/quicklook/glg_healpix_all_bn260109156.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260109156/quicklook/glg_lc_medres34_bn260109156.gif