TITLE: GCN CIRCULAR NUMBER: 36731 SUBJECT: EP240618a: GSP optical upper limit DATE: 24/06/22 09:48:46 GMT FROM: Wenxiong Li <liwenxiong1992@gmail.com> W. X. Li, S. J. Xue, (NAOC), M. Andrews, J. Farrah, D. A. Howell, M. Newsome, E. Padilla Gonzalez, C. McCully, and G. Terreran (Las Cumbres Observatory), on behalf of a larger collaboration, report: Following the detection of the fast X-ray transient EP240618a by the Einstein Probe (Sun et al., GCN 36690), we initiated observations of the fast X-ray transient location starting on June 18 at 7:43 UT (~2 hours after the trigger) in the r band. These observations were conducted using the 1-meter telescope at the Las Cumbres Observatory node located at McDonald Observatory in USA. No new optical source was detected in the co-added images within the EP/FXT error box down to ~21.5 mag. These observations were taken as part of the Global Supernova Project. View this GCN Circular online at https://gcn.nasa.gov/circulars/36731. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...