TITLE: GCN CIRCULAR NUMBER: 45459 SUBJECT: GRB 260818B: Further EP-FXT observation DATE: 26/08/28 17:30:16 GMT FROM: Yu-Han Yang at University of Rome Tor Vergata <yyang@roma2.infn.it> Yu-Han Yang, Eleonora Troja (U Rome), Jun Yang (ZZU), Qinyu Wu (NAO, CAS) report: We re-observed the field of the short GRB 260818B (SVOM/ECLAIRs; Cordier et al., GCN 45398) with EP-FXT through a ToO request. The observation started on 2026-08-27 at 16:48:47 UT (9.5 d post-trigger), with a total exposure of ~6 ks. Compared with the previous EP-FXT observation (Wu et al., GCN 45407), the X-ray source EPF_J025955.0+072535, located close to the radio source S10 (Schroeder et al., GCN 45418; Ricci et al. GCN 45452) and the candidate optical counterpart (Ducoin et al., GCN 45450; Yadav et al., GCN 45458), shows no significant variability. No fading X-ray source is found within the 90% confidence region of the ECLAIRs localization (Cordier et al., GCN 45398). Expanding the search region to 5-sigma level, we identify a fading X-ray source EPF_J025906.7+072552 at R.A. = 44.7791 deg, Dec. = 7.4315 deg (J2000), with a localization uncertainty of 10 arcsec (radius, 90% C.L., statistical and systematic). The source lies 9.7 arcmin away from the center of the ECLAIRs localization. We thank the EP team for scheduling and executing the ToO observation. View this GCN Circular online at https://gcn.nasa.gov/circulars/45459. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...