{
  "bibcode": "2025GCN.41079....1F",
  "circularId": 41079,
  "submittedHow": "web",
  "subject": "GRB 250713A: JinShan optical upper limits",
  "submitter": "syfu@nao.cas.cn",
  "createdOn": 1752433570197,
  "eventId": "GRB 250713A",
  "format": "text/plain",
  "body": "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:\n\nWe 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.\n\nNo 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.\n\nWe acknowledge the excellent support from T.Q. Chen for enabling these observations."
}