GCN Circular 44705

A. P. C. van Hoof (Radboud), G. Corcoran (UCD),  R. A. J. Eyles-Ferris (Leicester), J. Chacón (PUC), J. N. D. van Dalen (Radboud), P. G. Jonker (Radboud), report on behalf of a larger collaboration:

We observed the field of the Einstein Probe trigger WXT 01709266106, using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were obtained in the SDSS r (3x300 s) and z (5x200 s) bands, starting on 2026-05-26 at 21:01:29 UT (~3.4 hours after the WXT trigger).

We do not find any new, uncatalogued sources within the EP-WXT uncertainty region compared to Hyper Suprime-Cam and Legacy Survey images (DR10). From the stacked images we obtain the following 3-sigma upper limits:

r > 20.17
z > 19.40

These limits are in the AB system, were calibrated using nearby stars from the Pan-STARRS catalog and are not corrected for Galactic extinction.