TITLE:   GCN CIRCULAR
NUMBER:  43875
SUBJECT: EP260227a: Liverpool Telescope observations
DATE:    26/02/28 10:29:52 GMT
FROM:    Rob Eyles-Ferris at U of Leicester <raje1@leicester.ac.uk>

R. A. J. Eyles-Ferris and N. R. Tanvir (Leicester) report on behalf of a larger collaboration:

We observed the field of EP260227a (Wang et al., GCN 43869) with the 2m Liverpool Telescope on La Palma using the IO:O instrument. We obtained 6x150s exposures in each of the SDSS g’ r’ i’ z’ filters starting at 2026-02-28 04:25:03 UT, approximately 8.21 hours after the X-ray detection.

We detect the optical counterpart (Eyles-Ferris et al., GCN 43867; Li et al., GCN 43868; Fu et al., GCN 43873; Mandarakas et al., GCN 43874) in the r’, i’ and z’ bands. We measure the following magnitudes calibrated to Pan-STARRS and not corrected for Galactic extinction.

| t_mid (hours) | Filter |   AB magnitude   |
| ------------- | ------ | ---------------- |
|      8.35     |   g’   | >22.28 (3-sigma) |
|      8.63     |   i’   |  21.12 +/- 0.08  |
|      8.92     |   r’   |  21.61 +/- 0.22  |
|      9.21     |   z’   |  20.74 +/- 0.11  |

Compared to the photometry tabulated by Fu et al. (GCN 43873) and Mandarakas et al. (GCN 43874), our observations suggest the source has not faded significantly between these three epochs.