{
  "circularId": 38785,
  "submittedHow": "web",
  "body": "Yu-Zhang(NAOC), Junjie-Jin(NAOC), Haiyang-Mu(NAOC), Yuguang-Sun(NAOC), Zheng-Jie (NAOC), Zhou-Fan(NAOC), Hong-Wu(NAOC) report on behalf of a large collaboration:\nFollowing the detection of EP250101a by EP-WXT (Y. F. Liang et al., GCN 38778), we observed the field of EP250101a using the 80cm telescope at Xinglong Observatory, NAOC. We obtained 11x400s clear-band frames with a median time of 2025-01-03T01:08:55 i.e., 43 hr after the EP trigger. No uncatalogued optical transient is detected in the stacked images within the 3.2 arcmin EP/WXT error circle (Y. F. Liang et al., GCN 38778), down to 5-sigma limiting magnitudes of clear ~ 20.1, calibrated with Pan-STARRS sources in the field. Also, there is no apparent brightening for the catalogued sources within the error circle.",
  "subject": "EP250101a: Xinglong optical upper limit",
  "format": "text/plain",
  "createdOn": 1735874933958,
  "bibcode": "2025GCN.38785....1Y",
  "eventId": "EP250101a",
  "submitter": "Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong@nao.cas.cn>"
}