Confirmation of SRGt 062340.2-265751 as a nova-like cataclysmic variable with a possible magnetic nature

¹ Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
² Institut für Astronomie und Astrophysik Tübingen, Universität Tübingen, Sand 1, Tübingen, 72076 Baden-Württemberg, Germany
³ Potsdam University, Institute for Physics and Astronomy, Karl-Liebknecht-Straße 24/25, 14476 Potsdam, Germany
⁴ South African Astronomical Observatory, PO Box 9 Observatory Road, Observatory, 7935 Cape Town, South Africa
⁵ Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch, 7701 South Africa
⁶ Department of Physics, University of the Free State, PO Box 339 Bloemfontein, 9300 South Africa
⁷ Max-Planck-Institut für Extraterrestrische Physik, Gießenbachstraße 1, 85748 Garching, Germany
⁸ Department of Physics, Centre for Extragalactic Astronomy, Durham University, South Road, Durham, DH1 3LE UK

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 27 August 2025
Accepted: 4 November 2025

Abstract

SRGt 062340.2-265751, a cataclysmic variable identified by SRG/eROSITA thanks to its significant X-ray variability, remains poorly characterised despite the multi-wavelength follow-up. We present spectral and timing analyses from the first dedicated X-ray and ultraviolet observations with XMM-Newton, complemented by SRG/eROSITA data from four all-sky surveys (eRASS1-4) and ASAS-SN optical photometry. Our timing analysis reveals a > 8σ significant modulation at 3.6 ± 0.5 hours, likely representing the orbital period. Long-term ASAS-SN monitoring confirms the source as a VY Sculptoris-type nova-like system, while short-timescale X-ray and ultraviolet variability, down to a few minutes, suggests a possible underlying magnetic white dwarf. Two additional significant X-ray modulations at 43 ± 1 min and 36.0 ± 0.7 min tentatively point to the spin period of an intermediate polar. The best-fit XMM-Newton energy spectra reveal a multi-temperature thermal plasma (kT = 0.23, 0.94, and 5.2 keV), while the SRG/eROSITA spectra are consistent with a single-temperature thermal plasma of a few keV. We estimate unabsorbed X-ray luminosities of ≳10³² erg s⁻¹ (0.2–12 keV). Broadband spectral energy distribution modelling, from near-ultraviolet to infrared, indicates a disc-dominated system consistent with a nova-like classification. We discuss these results in the context of the source’s confirmed nova-like classification and its possible magnetic nature, a scenario increasingly supported by discoveries of intermediate polars exhibiting VY Sculptoris-type nova-like features.