GCN Circular 45973
Subject
GRB 261017A: Fermi GBM Final Real-time Localization
Event
Date
2026-10-17T16:15:32Z (7 hours 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 16:05:05 UT on 17 Oct 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261017A (trigger 813945910.098688 / 261017670).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 141.9, Dec = 14.8 (J2000 degrees, equivalent to J2000 09h 27m, 14d 48'), with a statistical uncertainty of 2.4 degrees.
The angle from the Fermi LAT boresight is 64.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261017670/quicklook/glg_skymap_all_bn261017670.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/bn261017670/quicklook/glg_healpix_all_bn261017670.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261017670/quicklook/glg_lc_medres34_bn261017670.gif