GCN Circular 44963
Subject
GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
Event
Date
2026-06-17T09:33:10Z (17 days ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
Web form
A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS),
V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI),
N. Pankov (IKI) report on behalf of GRB follow-up team
We observed the field of GRB 260610B discovered by Fermi (The Fermi
GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931),
and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m
telescope of SAO RAS + CCD photometer in Rc band on June 14,
15 and 16.
The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905;
Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al.,
GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918;
Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al.,
GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929;
Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al.,
GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958;
Dimple et al., GCN 44959) is detected in our stacked images
with the following brightness:
Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL
(mid,d) (n*s) (3-sigma)
2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3
2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8
2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9
This preliminary photometry is based on nearby SDSS stars
(using Lupton 2005 transformation equations) and not corrected
for Galactic extinction.
Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve.