Tomographic Simulations of Accretion Disks in Cataclysmic Variables — Flickering and Wind

Abstract

Cataclysmic Variables (CVs) are close binary systems where mass is transferred from a red dwarf star to a white dwarf star via an accretion disk. The flickering is observed as stochastic variations in the emitted radiation both in the continuum and in the emission line profiles.

The main goal of our simulations is to compare synthetic Doppler maps with observed ones, aiming to constrain the flickering properties and wind parameters.

A code was developed which generates synthetic emission line profiles of a geometrically thin and optically thick accretion disk. The simulation allows us to include flares in a particular disk region. The emission line flares may be integrated over arbitrary “exposure” times, producing the synthetic line profiles. Flickering Doppler maps are created using such synthetic time series. The presence of a wind inside the Roche lobe was also implemented. Radiative transfer effects in the lines where taken into account in order to reproduce the single peaked line profiles frequently seen in nova-like CVs.