Revisiting the X-ray Emission of the Asynchronous Polar V1432 Aql

TL;DR

This study analyzes X-ray data of the unique eclipsing asynchronous polar V1432 Aql, revealing details about its accretion geometry, spectral features, and modulation patterns, contributing to understanding magnetic accretion in such systems.

Contribution

It provides the first detailed X-ray analysis combining NuSTAR and XRT data, highlighting the accretion geometry and reflection effects in V1432 Aql, a rare asynchronous polar.

Findings

X-ray profile shows a low-intensity state, a dip at 0.6 phase, and a peak at 0.75 phase.

X-ray data exhibit orbital modulation rather than spin modulation.

Spectral analysis reveals significant reflection and a low total accretion rate.

Abstract

As the only eclipsing asynchronous polar, V1432 Aql provides an excellent laboratory to study the interaction between the accreted matter and the magnetic field. Here, we report an analysis of the X-ray data from the contemporaneous \nustar\ and \xrt\ observations. The X-ray data present a profile with a low-intensity state for almost half an orbital period, a dip at 0.6 phase, and a peak at 0.75 phase, which suggests that there was only one accretion region during the observation and the claim is supported by the spectral analysis. The comparison with the previous data indicates that the X-ray data have an orbital modulation, as the case in \sax, rather than a spin one observed in \rosat. We attribute the orbit and spin modulations to the different accretion geometries at work. The spectral analysis of the wide-band data presents a significant reflection effect, a commonly observed soft X-ray temperature, and the energy balance in V1432 Aql . Additionally, we obtained a low total accretion rate of 1.3 $\times$ 10$^{-10}$ M$_{\odot}$ yr$^{-1}$ and a high specific accretion rate of 3.8 g cm$^{-2}$ s$^{-1}$ which explains the strong reflection from the surface of the white dwarf. However, due to its complex emission, a more physical understanding of its accretion geometry is still outstanding.