PALOMA: A Magnetic CV between Polars and Intermediate Polars

TL;DR

This paper analyzes X-ray and optical data of the magnetic cataclysmic variable Paloma, revealing its dual characteristics of polars and intermediate polars through periodicities, spectral modeling, and phase-resolved spectroscopy.

Contribution

It provides the first detailed phase-resolved spectral analysis of Paloma, demonstrating its hybrid nature between polars and intermediate polars.

Findings

Detected orbital and spin periods consistent with previous observations.

X-ray spectrum fitted by two-temperature plasma models with soft excess.

Spectral parameters vary with orbital and spin phases.

Abstract

We present analyses of archival X-ray data obtained from the XMM-Newton satellite and optical photometric data obtained from 1 m class telescopes of ARIES, Nainital of a magnetic cataclysmic variable (MCV) Paloma. Two persistent periods at 156 $\pm$ 1 minutes and 130 $\pm$ 1 minutes are present in the X-ray data, which we interpret as the orbital and spin periods, respectively. These periods are similar to those obtained from the previous as well as new optical photometric observations. The soft-X-ray excess seen in the X-ray spectrum of Paloma and the averaged X-ray spectra are well fitted by two-temperature plasma models with temperatures of 0.10$_{-0.01}^{+0.02}$ and 13.0$_{-0.5}^{+0.5}$ keV with an Fe K$\alpha$ line and an absorbing column density of 4.6 $\times$ 10^{22} cm^{-2}. This material partially covers 60 $\pm$ 2 % of the X-ray source. We also present the orbital and spin-phase-resolved spectroscopy of Paloma in the $0.3 - 10.0$ keV energy band and find that the X-ray spectral parameters show orbital and spin-phase dependencies. New results obtained from optical and X-ray studies of Paloma indicate that it belongs to a class of a few magnetic CVs that seem to have the characteristics of both the polars and the intermediate polars.