GCN 45209: EP260723a: EP-FXT follow-up observation

K. R. Ni (CCNU), Y. J. Zhang (PKU), X. H. Tang (THU), H. Sun (NAOC) on behalf of the Einstein Probe (EP) team:   
EP-FXT performed a follow-up observation of EP260723a detected by EP-WXT (Zhang et al., GCN 45201). The observation started at 2026-07-24 08:44:22 UTC, about 13.8 hr after the WXT detection, with a total exposure time of around 3.0 ks.
On-ground analysis of the FXT data found no significant uncatalogued X-ray source in either the individual FXT-A or FXT-B image. After stacking the FXT-A and FXT-B data, a weak X-ray excess, with an S/N of approximately 2.2, was found at the position of the optical counterpart reported by the Nordic Optical Telescope (NOT; He et al., GCN 45203):
R.A. (J2000) = 2.97518 deg
Dec. (J2000) = −12.09851 deg
The optical counterpart was initially reported by the Liverpool Telescope (Eyles-Ferris et al., GCN 45202) and was subsequently confirmed by NOT (He et al., GCN 45203), COLIBRÍ (Basa et al., GCN 45204), and SVOM/VT (Ma et al., GCN 45205).
Given the low statistical significance, it is still unclear whether this weak X-ray excess is associated with EP260723a. The limited number of source counts does not allow meaningful spectral analysis.
Further EP-FXT follow-up observations will be arranged.
Launched on January 9, 2024, EP is a space X-ray observatory designed to monitor the dynamic soft X-ray sky and perform follow-up observations of newly discovered transients (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).