GCN Circular 40269

Subject

EP250427a: LT optical counterpart detection

Event

EP250427a

Date

2025-04-28T07:34:08Z (6 months ago)

From

qiang xi <xiqiang051@gmail.com>

Via

Web form

Qiang Xi (UCAS), I. Pérez-Fournon, F. Poidevin, D.S. Aguado, A. López-Oramas, D. Nespral (IAC and ULL), N.C. Sun, Z.X. Niu (UCAS and NAOC), W.X. Li, Y.N. Wang (NAOC):

We observed the field of the Einstein Probe WXT event EP250427a (Wang et al., GCN circ. 40257

), using the 2.0-meter Liverpool Telescope (LT) located at the Observatorio del Roque de los Muchachos, La Palma, Spain. Observations were carried out with the IO:O instrument, starting on 2025-04-28 at 03:34UT.

We obtained a series of 3x60s exposures in each of the u, g, r, i, and z filters. An uncatalogued source is clearly detected in griz bands at the optical counterpart position first reported by Perez-Garcia et al. (GCN circ. 40259

) and with other optical and near-infrared detections reported by Liu et al. (GCN circ. ), Becerra et al. (GCN circ. ), Brivio et al. (GCN circ. ), Chornock et al. (GCN circ. ), Saccardi et al. (GCN circ. ), Pérez-Fournon et al. ( GCN circ. ).

The preliminary r-band photometry for this source is reported below, calibrated with the Pan-STARRS catalog, and not corrected for Galactic extinction.

UTC start	mag	error	filter	exposure time (sec)
2025-04-28 03:42:36.919	20.14	0.17	SDSS-r	3×60