# The structure of accretion flows in nova-like cataclysmic variables: RW Sextantis and 1RXS J064434.5+334451

## TL;DR

This study analyzes emission line profiles in nova-like cataclysmic variables RW Sextantis and 1RXS J064434.5+334451, revealing the origin of different emission components and proposing a model for the accretion disc structure.

## Contribution

It identifies the origin of narrow and wide emission components in these systems and suggests a common structure in similar long-period nova-like variables.

## Key findings

- The narrow component originates from the irradiated face of the secondary star.
- The wide component emanates from the outer side of the accretion disc.
- The wide component is common in similar long-period nova-like systems.

## Abstract

New time-resolved optical spectroscopic echelle observations of the nova-like cataclysmic variable RW Sextantis were obtained, with the aim to study the properties of emission features in the system. The profile of the H_alpha emission line can be clearly divided into two (`narrow' and `wide') components. Similar emission profiles are observed in another nova-like system, 1RXS~J064434.5+33445, for which we also reanalysed the spectral data and redetermined the system parameters. The source of the `narrow', low-velocity component is the irradiated face of the secondary star. We disentangled and removed the `narrow' component from the H_alpha profile to study the origin and structure of the region emitting the wide component. We found that the `wide' component is not related to the white dwarf or the wind from the central part of the accretion disc, but is emanated from the outer side of the disc. Inspection of literature on similar systems indicates that this feature is common for some other long-period nova-like variables. We propose that the source of the `wide' component is an extended, low-velocity region in the outskirts of the opposite side of the accretion disc, with respect to the collision point of the accretion stream and the disc.