GCN Circular 45303
Subject
EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
Event
Date
2026-08-07T09:33:18Z (15 days ago)
From
Rob Eyles-Ferris at U of Leicester <raje1@leicester.ac.uk>
Via
Web form
R. A. J. Eyles-Ferris (Leicester), G. Corcoran (UCD), P. G. Jonker (Radboud), J. N. D. van Dalen (Radboud) and A. Martin-Carrillo (UCD) report on behalf of a larger collaboration:
We observed the field of the Einstein Probe fast X-ray transient EP260806a (Li et al., GCN 45299) with the 2m Liverpool Telescope on La Palma using the IO:O instrument. We obtained 6x150 s and 6x150 s exposures in each of the SDSS r’ and z’ filters starting at 2026-08-07 01:24:49 UT, approximately 2.38 hours after the X-ray detection.
We performed image subtraction on the stacked images using PanSTARRS templates and detect the optical counterpart (He at al., GCN 45300; de Ugarte Postigo et al., GCN 45302) in both bands. No other sources are detected within the EP/FXT error region (Li et al., GCN 45299).
In our subtracted images, we measure
r = 19.22 +/- 0.03
z = 19.53 +/- 0.04
Our photometry is calibrated to PanSTARRS and not corrected for Galactic extinction.
The blue colour is broadly consistent with an AGN outburst as suggested by de Ugarte Postigo et al. (GCN 45302) but may also be evidence of a fast rising tidal disruption event origin. Further observations are encouraged.