GCN Circular 45280
Subject
GRB 260708A: LCO further optical observations show supernova features
Event
Date
2026-08-04T02:02:22Z (2 months ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Y.Y. Shi (GXU), C. Wu, L.P. Xin (NAOC), A. Saccardi, D. Turpin (CEA/Irfu), Y.X. Guan, S.J. Yin (GXU) report on behalf of the SVOM mission team:
We have continued monitoring the optical counterpart (Shilova et al., GCN 45123; Freeberg et al., GCN 45127; Sheng et al., GCN 45147) of the Fermi long GRB 260708A (Fermi/GBM Team, GCN 45115; Fermi-LAT, Holzmann Airasca et al., GCN 45117), using SINISTRO instruments mounted on 1-m telescopes of the LCO global network.
We observed the optical counterpart in imaging using the g, r, i bands from 2026-07-11 (3.56 days after the trigger) to 2026-08-02 (25.03 days after the trigger).
The optical counterpart shows a color change toward blue. It was measured to have a brightness of g=19.56+/-0.02 mag at 3.56 days post-trigger and g=18.88+/-0.02 mag at 11.48 days respectively, which show a rebrightening of the counterpart with a rise time of ~11.5 days post-trigger. Photometry was calibrated against the UCAC4 catalog, without template subtraction and not corrected for Galactic extinction.
We suggest that it is likely the supernova associated with the burst. Multi-band photometric and spectroscopic observations are encouraged.
This project is funded by the SVOM collaboration.