{
  "body": "Min-He (NAOC), Junjie-Jin (NAOC), Haiyang-Mu (NAOC), Sen-Liu (NAOC), Yiming-Mao (NAOC), Pengliang-Du (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report on behalf of a large collaboration:\n\nFollowing the detection of EP-WXT01709259790, we observed the field of EP-WXT01709259790 using the 2.16-m telescope at Xinglong Observatory, NAOC. We obtained 3x300s clear-band frames with a median time of 2026-04-10T12:16:23, 52 minutes after the EP trigger.\n\nNo uncatalogued optical transient is detected in the stacked images within the 3 arcmin EP/WXT error circle (WXT01709259790), down to 3-sigma limiting magnitudes of 22.18 mag for 2.16-m, calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle.",
  "createdOn": 1775830724483,
  "bibcode": "2026GCN.44254....1M",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong@nao.cas.cn>",
  "format": "text/plain",
  "subject": "EP-WXT01709259790: Xinglong optical upper limit",
  "circularId": 44254,
  "editedOn": 1775831382162,
  "submitter": "Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong@nao.cas.cn>",
  "version": 2,
  "submittedHow": "web"
}