TITLE:   GCN CIRCULAR
NUMBER:  46154
SUBJECT: GRB 261104A: LCO optical upper limits
DATE:    26/11/05 01:30:27 GMT
FROM:    SVOM_group <svomgroup@bao.ac.cn>

S.J. Yin(GXU),D. Turpin,  A. Saccardi , J. T. Palmerio (CEA/Irfu),Y.X. Guan(GXU), C. Wu , L.P. Xin,(NAOC), Y.Y. Shi(GXU), X.H. Han(NAOC), M. Gnaoui (IAP), L.Zhang (IHEP), A. Li (BNU),
 report on behalf of the SVOM mission team:

We observed the field of GRB 261104A (detected by SVOM burst-id sb26110402
 (Bernardini et al., GCN 46150) with the LCO 1m telescope at South Afican Astronomical Observatory equipped with the Sinistro instrument.

Our observation started on 2026-11-04T21:51:12.583 UTC (about 1.24 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r filter.

In the stacked image, we do not detect any new source within the SVOM/ECLAIRs error box. We measure the following upper limit calibrated against the DESI DR10 catalog, and not corrected for Galactic extinction:

r > 22.31 AB (5-sigma, mid-time 1.33 hr after the trigger).

This project is funded by the SVOM collaboration.