TITLE:   GCN CIRCULAR
NUMBER:  45573
SUBJECT: GRB 260915A: LCO optical upper limits
DATE:    26/09/15 04:14:02 GMT
FROM:    SVOM_group <svomgroup@bao.ac.cn>

S.J. Yin (GXU),C. Wu, L.P. Xin (NAOC),D. Turpin (CEA/Irfu), A. Saccardi (CEA/Irfu), W. Tan (IHEP), Y. N. Ma (NAOC) report on behalf of the SVOM mission team:
 
We observed the field of GRB 260915A (SVOM burst-id sb26091501） detected by SVOM (Liang et al., GCN 45570) with the LCO 1m telescope at Cerro Tololo Observatory and Teide Observatory equipped with the Sinistro instrument.
 
Our observation started on 2026-09-15 at 01:42:33 UT (about 30.5 min after the trigger) and we obtained 3x200 s exposures in the SDSS r and 3x200 s exposures in the 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  Pan-STARRS DR1 catalog, and not corrected for Galactic extinction:

r > 21.1 AB (5-sigma, mid-time 35.9 min after the trigger);
z > 20.5 AB (5-sigma, mid-time 1.37 hr after the trigger).
 
This project is funded by the SVOM collaboration.