TITLE:   GCN CIRCULAR
NUMBER:  45608
SUBJECT: GRB 260917B: LCO optical observation
DATE:    26/09/17 08:36:34 GMT
FROM:    SVOM_group <svomgroup@bao.ac.cn>

S. J. Yin (GXU), A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud),  C. Wu (NAOC), Y.X. Guan, Y.Y. Shi(GXU),  K. Liu (GXU), report on behalf of the SVOM mission team:

We observed the field of GRB 260917B detected by SVOM/ECLAIRs (He et al., GCN 45606) with the LCO 1m telescope at Teide Observatory equipped with the Sinistro instrument.

Our observation started on 2026-09-17 at 04:53:16 UT (about 1.02 hr after the trigger)  and we obtained 6x200 s exposures in the SDSS r and 3x200 s exposures in the Pan-STARRS z filters.

The optical candidate (Dornic et al., GCN 45607) is detected in our images. We measure the following magnitudes calibrated against the Pan-STARRS DR1 catalog, and not corrected for Galactic extinction:

r = 21.34 +/- 0.11 AB (mid-time 1.24 hr after the trigger).
z = 20.16 +/- 0.14 AB (mid-time 1.16 hr after the trigger).

This project is funded by the SVOM collaboration.