GCN Circular 45140
Subject
GRB 260708A: LCO optical observations
Event
Date
2026-07-12T05:22:33Z (8 days 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) report on behalf of the SVOM mission team:
We observed the field of the GRB 260708A detected by Fermi/GBM(Fermi GBM team, GCN 45115; GCN 45124) and Fermi/LAT (Holzmann Airasca et al., GCN 45117) with the LCO 1m telescope at Cerro Tololo Inter-American Observatory equipped with the Sinistro instrument.
Our observation started on 2026-07-11 at 23:37:53 UT (about 3.56 day after the trigger) and we obtained 3x200 s exposures in the SDSS g, r and i filters.
The optical counterpart (Shilova et al., GCN 45123; Freeberg et al., GCN 45127) is clearly detected in our images. We measure the following magnitudes calibrated against the UCAC4 catalog, and not corrected for Galactic extinction:
g = 19.56 +/- 0.02 AB (mid-time 3.56 day after the trigger);
r = 19.21 +/- 0.02 AB (mid-time 3.60 day after the trigger);
i = 19.17 +/- 0.03 AB (mid-time 3.59 day after the trigger).
It appears to be fading compared with the results reported by Shilova et al. (GCN 45123) and Freeberg et al.(GCN 45127).
This project is funded by the SVOM collaboration.