GCN Circular 45797
Subject
GRB 261003A: Fermi GBM Final Real-time Localization
Event
Date
2026-10-03T01:29:04Z (a day 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 01:18:35 UT on 3 Oct 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261003A (trigger 812683120.140818 / 261003055).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 306.5, Dec = 45.7 (J2000 degrees, equivalent to J2000 20h 26m, 45d 42'), with a statistical uncertainty of 20.7 degrees.
The angle from the Fermi LAT boresight is 87.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261003055/quicklook/glg_skymap_all_bn261003055.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/bn261003055/quicklook/glg_healpix_all_bn261003055.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261003055/quicklook/glg_lc_medres34_bn261003055.gif