TITLE:   GCN CIRCULAR
NUMBER:  43616
SUBJECT: GRB 260204A: LCO optical upper limits
DATE:    26/02/04 21:16:28 GMT
FROM:    SVOM_group <svomgroup@bao.ac.cn>

D. Turpin (CEA/Irfu), A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud), B. Cordier (CEA/Irfu), report on behalf of the SVOM mission team:

We observed the field of GRB 260204A (Pillas et al., GCN 43613) with the LCO 1-m telescope at Siding Spring Observatory equipped with the Sinistro instrument.

Our observation started on 2026-02-04 at 15:10:42 UT (about 22 min after the trigger) and we obtained 3x200 s in each of the SDSS r and Pan-STARRS z filters. 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 PanSTARRS DR1 catalog, and not corrected for Galactic extinction:

r > 20.3 AB (5-sigma, mid-time 25.7 min after the trigger);
z > 19.4 AB (5-sigma, mid-time 38.4 min after the trigger).

This project is funded by the SVOM collaboration.