GRB 261025B
GCN Circular 46158
Subject
IPN triangulation of GRB 261025B (short)
Date
2026-11-05T13:56:06Z (2 days ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,
and
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi-GBM team, report:
The short-duration GRB 261025B
(Fermi-GBM detection: The Fermi GBM team, GCN 46029)
was detected by Fermi (GBM trigger 814642716) and
Konus-Wind at about 63512 s UT (17:38:32).
We have triangulated it to the 3 sigma localization region
whose area is 45.7 sq. deg, and its maximum
dimension is 43 deg (the minimum one is 1.1 deg).
This localization may be improved.
A triangulation map and HEALPix FITS files are posted at
http://www.ioffe.ru/LEA/GRBs/GRB261025_T63508/IPN/
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.
The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular.
GCN Circular 46029
Subject
GRB 261025B: Fermi GBM Final Real-time Localization
Date
2026-10-25T17:46:25Z (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 SHORT GRB
At 17:38:31 UT on 25 Oct 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261025B (trigger 814642716.94305 / 261025735).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 258.2, Dec = 24.8 (J2000 degrees, equivalent to J2000 17h 12m, 24d 48'), with a statistical uncertainty of 4.6 degrees.
The angle from the Fermi LAT boresight is 30.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261025735/quicklook/glg_skymap_all_bn261025735.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/bn261025735/quicklook/glg_healpix_all_bn261025735.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261025735/quicklook/glg_lc_medres34_bn261025735.gif