TITLE: GCN CIRCULAR NUMBER: 44140 SUBJECT: EP-WXT trigger 01709259209: TRT optical counterpart detection DATE: 26/03/29 11:32:38 GMT FROM: Zipei Zhu at NAOC <zpzhu@nao.cas.cn> Z.P. Zhu (NAOC), S. Tinyanont, K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), J. An, X. Liu, S.Q. Jiang, L.B. He, N.C. Sun, W.X. Li, D. Xu (NAOC), S.Y. Fu (HUST) report on behalf of a large collaboration: We observed the field of EP260329a detected by the Einstein Probe (EP) (Trigger ID: 01709259209 ), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Sierra Remote Observatories in California. We obtained several exposure frames in the R filter. The optical counterpart located at: R.A. (J2000) = 12:05:14.95 () Dec.( J2000) = +4:21:05.8 with an uncertainty of ~ 0.8 arcsec. The uncatalogued source is clearly detected in the stacked image with the measured brightness of R = 18.4 +/- 0.1 at a mid-time of 10:47:20 UTC on 2026-03-29., consistant with the optical candidate reported by LCO (Li et al., GCN 44139), calibrated using nearby stars from the Pan-STARRS catalog and are not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44140. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...