Breaking the Degeneracy in Magnetic Cataclysmic Variable X-Ray Spectral Modeling Using X-Ray Light Curves

Fecha

2021

Profesor Guía

Formato del documento

Articulo

ORCID Autor

Título de la revista

ISSN de la revista

Título del volumen

Editor

American Astronomical Society (Aas)

Ubicación

ISBN

ISSN

item.page.issne

Facultad

Facultad de Ciencias

Departamento o Escuela

Instituto de Fisica y Astronomia

Determinador

Recolector

Especie

Nota general

Resumen

We present an analysis of mock X-ray spectra and light curves of magnetic cataclysmic variables using an upgraded version of the 3D cyclops code. This 3D representation of the accretion flow allows us to properly model total and partial occultation of the postshock region by the white dwarf as well as the modulation of the X-ray light curves due to the phase-dependent extinction of the preshock region. We carried out detailed postshock region modeling in a four-dimensional parameter space by varying the white dwarf mass and magnetic field strength as well as the magnetosphere radius and the specific accretion rate. To calculate the postshock region temperature and density profiles, we assumed equipartition between ions and electrons; took into account the white dwarf gravitational potential, the finite size of the magnetosphere, and a dipole-like magnetic field geometry; and considered cooling by both bremsstrahlung and cyclotron radiative processes. By investigating the impact of the parameters on the resulting X-ray continuum spectra, we show that there is an inevitable degeneracy in the four-dimensional parameter space investigated here, which compromises X-ray continuum spectral fitting strategies and can lead to incorrect parameter estimates. However, the inclusion of X-ray light curves in different energy ranges can break this degeneracy, and it therefore remains, in principle, possible to use X-ray data to derive fundamental parameters of magnetic cataclysmic variables, which represents an essential step toward understanding their formation and evolution.

Descripción

Lugar de Publicación

Auspiciador

Palabras clave

CATACLYSMIC VARIABLE STARS, MAGNETIC VARIABLE STARS

Licencia

© 2021. The American Astronomical Society. All rights reserved.

URL Licencia