TITLE: GCN CIRCULAR NUMBER: 43588 SUBJECT: EP260131a: Xinglong optical upper limit DATE: 26/02/01 04:16:49 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong@nao.cas.cn> Haiyang-Mu (NAOC),Junjie-Jin (NAOC), Feng-Xiao (NAOC), Pengliang-Du (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report: Following the detection of EP260131a by EP-WXT (GCN Circular 43574,GCN Circular 43577,GCN Circular 43578), we observed the field of EP260131a using the 2.16-m telescope at Xinglong Observatory, NAOC. We obtained 300s r-band frames with a median time of (2026-01-31 16:25:55(UT)) 13 hr after the EP trigger. No uncatalogued optical transient is detected in the stacked images within the 3 arcmin EP/WXT error circle (GCN Circular 43574,GCN Circular 43578), down to 5-sigma limiting magnitudes of r ~ 19.1(not good day with thin cloud and bad seeing), calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle. Based on the location of the report(GCN Circular 43574,GCN Circular 43578), the target was not observed. View this GCN Circular online at https://gcn.nasa.gov/circulars/43588. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...