An investigation of a magnetic cataclysmic variable with a period of 14.1 ks

TL;DR

This paper reports the discovery and analysis of a magnetic cataclysmic variable with a 14.1 ks period, characterized by X-ray and optical observations indicating a low-accretion-rate polar with a potential radio counterpart.

Contribution

The study identifies a new magnetic CV from Chandra data, characterizes its X-ray and optical properties, and suggests it is a low-accretion-rate polar, adding to the understanding of such systems.

Findings

Detected a 14.1 ks periodicity in X-ray light curves.

Spectral analysis indicates a multi-temperature hot plasma.

Possible radio counterpart identified, requiring further confirmation.

Abstract

Magnetic cataclysmic variables (CVs) contain a white dwarf with magnetic field strong enough to control the accretion flow from a late type secondary. In this paper, we discover a magnetic CV (CXOGSG J215544.4+380116) from the $Chandra$ archive data. The X-ray light curves show a significant period of 14.1 ks, and the X-ray spectra can be described by a multi-temperature hot thermal plasma, suggesting the source as a magnetic CV. The broad dip in the X-ray light curve is due to the eclipse of the primary magnetic pole, and the additional dip in the bright phase of the soft and medium bands may be caused by the accretion stream crossing our line of sight to the primary pole. Follow-up optical spectra show features of an M2--M4 dwarf dominating the red band and a WD which is responsible for the weak upturn in the blue band. The mass ($\sim$ 0.4 $M_{\odot}$) and radius ($\sim$ 0.4 $R_{\odot}$) for the M dwarf are obtained using CV evolution models and empirical relations between the orbital period and the mass/radius. The estimated low X-ray luminosity and accretion rate may suggest the source as a low-accretion-rate polar. In addition, Very Large Array observations reveal a possible radio counterpart to the X-ray source, but with a low significance. Further radio observations with high quality are needed to confirm the radio counterpart and explore the properties of this binary system.