GCN Circular 38907
Subject
EP250108a: optical follow-up observations with the Liverpool Telescope
Event
Date
2025-01-11T11:54:00Z (a year ago)
From
Amit Kumar at Royal Holloway - UoL/ U of Warwick, UK <amitkundu515@gmail.com>
Via
Web form
A. Kumar, J. R. Maund (RHUL), N. C. Sun (UCAS), W. X. Li, Y. N. Wang (NAOC), and K. Wiersema (Herts) report:
We conducted optical follow-up observations of the possible optical counterpart (Eyles-Ferris, GCN 38878; Zhu et al., GCN 38885; Malesani et al., GCN 38902) of the EP-detected X-ray transient EP250108a (Li et al., GCNs 38861 and 38888) using the IO:O imager at the 2m Liverpool Telescope. Multi-band observations were performed starting on 2025-01-09 UT 22:06:09.685 and 2025-01-10 UT 19:41:48.380 (nearly 1.4 and 2.3 days post-trigger, respectively).
Based on our preliminary analysis:
In the stacked g-band image observed at ~1.4 days post-trigger, we detected the optical counterpart of EP250108a at a position consistent with the optical counterpart identified by Eyles-Ferris, GCN 38878. Based on our preliminary PSF photometry, the magnitude of the counterpart in the stacked g-band image is 20.2 ± 0.1 (AB); consistent with the magnitudes reported by Zhu et al., GCN 38885. The counterpart exhibits clear signs of brightening (as suggested by Zhu et al., GCN 38885), and we recommend continued follow-up observations.
The quoted magnitudes are not corrected for the Galactic extinction in the direction of the EP-transient.
Further analysis and observations are planned. This circular may be cited.