GCN Circular 46049
Subject
GRB 261026A: Ondrejov D50 optical limit
Event
Date
2026-10-26T21:27:28Z (5 days ago)
From
Filip Novotný at Masaryk University <filip.novotny@talentovani.cz>
Via
Web form
F. Novotny, J. Strobl, M. Jelinek and R. Hudec (ASU CAS Ondrejov) report:
We observed the position of GRB 261026A, detected by SVOM/ECLAIRs and
SVOM/GRM (Goto et al., GCN 46030), with the D50 telescope of the
Astronomical Institute Ondrejov, near Prague, Czech Republic. We obtained
a series of 60s Sloan i'-band exposures between 17:05 and 20:58 UT on
2026 October 26, i.e. 10.9-14.8 h after the trigger. Part of the series
was affected by clouds; 192 frames with good transparency were combined.
We do not detect the optical counterpart at the SVOM/VT position
(RA, Dec = 337.35317, +27.02623; Wu et al., GCN 46035), neither in single
images (3-sigma limit i'>17.3-18.8) nor in the combined 11520 s image
(mean epoch T0+13.13 h, 3-sigma limit i'>20.6).
Photometry is calibrated in Sloan i' (AB system) against ATLAS-RefCat2
field stars, not corrected for Galactic extinction.