TITLE:   GCN CIRCULAR
NUMBER:  41079
SUBJECT: GRB 250713A: JinShan optical upper limits
DATE:    25/07/13 19:06:10 GMT
FROM:    syfu@nao.cas.cn

S.Y. Fu(HUST), S.Q. Jiang, J. An, X. Liu, Z.P. Zhu, L.B. He, D. Xu (NAOC), J.Z. Liu (XAO) report on behalf of a large collaboration:

We observed the field of GRB250713A (sb25071320) detected by SVOM/ECLAIRs (Maggi et al., GCN 41078), using the 50cm & 100cm telescopes of the JinShan project, located at Altay, Xinjiang, China. Observations began at 17:08:08 UT on 2025-07-13, i.e., 102 seconds after the trigger, and a series of frames were obtained in the Sloan r, i and z-band.

No new optical source is detected within the SVOM/MXT error circle, down to 5-sigma upper limits of r ~ 21.0, i ~ 17.7 and z ~ 20.8, calibrated with nearby Pan-STARRS stars and not corrected for Galactic extinction.

We acknowledge the excellent support from T.Q. Chen for enabling these observations.