TITLE: GCN CIRCULAR NUMBER: 43390 SUBJECT: EP260110a: TRT optical upper limits DATE: 26/01/13 16:28:35 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 EP260110a detected by the Einstein Probe (EP) (Zhang et al., GCN 43367), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Sierra Remote Observatories in California. We obtained several 360 s frames in the R filter. Observations started at 07:38:55 UTC on 2026-01-11, i.e., 0.44 day after the EP/WXT trigger time. No new source is detected within or at the border of the EP/FXT error region (Zhang et al., GCN 43363), being consistent with the non-detection reported at other telescopes (Perez-Garcia et al., GCN 43364; Kang et al., GCN 43365; Antier et al., GCN 43366; Zheng et al., GCN 43368; Lipunov et al., GCN 43372; Li et al., GCN 43375). From the stacked images we obtain the following 5-sigma upper limits in Vega magnitude: | Mid-time(d) | filter | upper limit | site | | ------------- | -------- | ------------- | ------ | | 0.46 | R | > 19.6 | SRO | | 1.45 | R | > 20.9 | SRO | | 2.44 | R | > 21.0 | SRO | calibrated using nearby stars from the Pan-STARRS DR1 catalog and are not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43390. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...