GCN Circular 46236
R. A. J. Eyles-Ferris (Leicester), J. Chácon (PUC), P. G. Jonker (Radboud), D. B. Malesani (DAWN/NBI and Radboud) and A. A. Chrimes (Radboud) report on behalf of a larger collaboration:
We observed the field of the fast X-ray transient EP261111a detected by Einstein Probe (Huang et al., GCN 46226; Li et al., GCN 46235) with LCO 1-m telescopes located at McDonald Observatory (USA) and equipped with SINISTRO instruments. Observations consisted of a sequence of 6 x 300 s exposures in each of the SDSS r and z bands starting at 2026-11-12 01:59:08 UT (~12.4 h post trigger) and 2026-11-12 08:12:07 UT (~18.8 h post trigger), respectively.
We performed image subtraction using PanSTARRS template images and compared the stacked and templates manually. We do not detect any new source inside the Einstein Probe Follow-up X-ray Telescope uncertainty region (Li et al., GCN 46235) to 3-sigma limiting magnitudes of r > 22.7 and z > 22.3 in either our stacked images or the subtractions. Our non-detections are consistent with those of Jin et al. (GCN 46227) and Buckley et al. (GCN 46230).
Our upper limits are in AB magnitudes, calibrated using nearby stars from the PanSTARRS catalogue, and are not corrected for Galactic extinction.