GCN 45212: EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening

R. A. J. Eyles-Ferris (Leicester) reports on behalf of a larger collaboration:

We observed the field of the Einstein Probe fast X-ray transient EP260723a (Zhang et al., GCN 45201; Ni et al. GCN 45209) with the 2m Liverpool Telescope on La Palma using the IO:O instrument. We obtained 12x150 s and 12x150 s exposures in each of the SDSS r’ and z’ filters starting at 2026-07-25 03:26:08 UT, approximately 32.5 hours after the X-ray detection.

We detect the optical counterpart (Eyles-Ferris et al., GCN 45202; He et al., GCN 45203; Basa et al., GCN 45204; Ma et al., GCN 45205) in both bands at AB magnitudes of r = 22.17 +/- 0.08 and z = 21.48 +/- 0.13. Our photometry is calibrated to PanSTARRS and not corrected for Galactic extinction.

We note that these magnitudes are consistent with those reported by Basa et al. (GCN 45204) approximately 19 hours earlier, suggesting an extended optical plateau or rebrightening. Further observations are planned.