English

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

High Energy Astrophysical Phenomena 2025-12-01 v2 Solar and Stellar Astrophysics

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\sigma significant modulation at 3.6 ±\pm 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 ±\pm 1 min and 36.0 ±\pm 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 (kTkT = 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 \gtrsim103210^{32} erg s1^{-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.

Keywords

Cite

@article{arxiv.2511.04738,
  title  = {Confirmation of SRGt 062340.2-265751 as a nova-like cataclysmic variable with a possible magnetic nature},
  author = {V. A. Cúneo and A. D. Schwope and J. Kurpas and A. Avakyan and J. Brink and D. A. H. Buckley and C. Maitra and M. Veresvarska},
  journal= {arXiv preprint arXiv:2511.04738},
  year   = {2025}
}

Comments

Accepted for publication in A&A