GCN Circular 43523
Subject
EP260126a: Further NOT optical upper limits
Event
Date
2026-01-27T09:56:26Z (7 days ago)
From
Rob Eyles-Ferris at U of Leicester <raje1@leicester.ac.uk>
Via
Web form
R. A. J. Eyles-Ferris (Leicester), D. B. Malesani (DAWN/NBI and Radboud), J. A. Quirola-Vasquez (Radboud), J. N. D. van Dalen (Radboud), G. Corcoran (UCD), P. G. Jonker (Radboud), A. Martin-Carrillo (UCD) and A. J. Levan (Radboud) report on behalf of a larger collaboration:
We observed the field of the fast X-ray transient EP260126a (Fu et al., GCN 43520) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were obtained in the SDSS r and z bands, consisting of 3x300 s and 5x200 s exposures, respectively, starting on 2026-01-26 at 23:08:13 UTC (~18.7 hr after the WXT trigger).
No new source is detected within or at the border of the EP/FXT uncertainty region (Fu et al., GCN 43520) compared to Legacy DR10. From the stacked images, we obtain the following 3-sigma upper limits:
r > 24.3
z > 23.2
These upper limits are in AB magnitudes, calibrated using nearby stars from the Pan-STARRS catalog, and are not corrected for Galactic extinction. Our non-detection is consistent with the results of Zhu et al. (GCN 43521) and Globus et al. (GCN 43522).