TITLE: GCN CIRCULAR NUMBER: 40269 SUBJECT: EP250427a: LT optical counterpart detection DATE: 25/04/28 07:34:08 GMT FROM: qiang xi xiqiang051@gmail.com
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. 40260), Becerra et al. (GCN circ. 40261), Brivio et al. (GCN circ. 40264), Chornock et al. (GCN circ. 40265), Saccardi et al. (GCN circ. 40266), Pérez-Fournon et al. ( GCN circ. 40267).
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 |
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