GCN Circular 43728

Subject

EP/WXT 01709258378: NOT optical upper limits

Date

2026-02-14T01:29:01Z (2 days ago)

From

Laura Cotter at University College Dublin <laura.cotter@ucdconnect.ie>

Via

Web form

L. Cotter (UCD), G. Corcoran (UCD), A. Martin-Carrillo (UCD), D. B. Malesani (DAWN/NBI and Radboud), F. E. Bauer (SSI and UTA) and P. G. Jonker (Radboud)  report on behalf of a larger collaboration:

We observed the field of the fast X-ray transient WXT 01709258378 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 2026-02-13 at 23:08:39 UT (3.17 hours after the WXT trigger).

We do not find any new, uncatalogued sources within the EP/WXT uncertainty region. From the stacked images we obtain the following 3-sigma upper limits:

r>24.0
z>22.3

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