Time-domain studies of compact binaries

Project Description:

Cataclysmic variables (CVs) are semi-detached compact binaries consisting of a white dwarf (WD) and a low-mass main-sequence star – usually a red-dwarf (Warner, 1995). The close proximity of the two stars allows matter (gas) to be transferred from the red dwarf to the WD via a Roche lobe overflow. CVs offer astronomers a laboratory to study a wide range of phenomenon including: the physics of accretion onto compact objects such as WDs, the formation and evolution of close binaries – including common-envelope processes as well as their population synthesis by studying large sample of these systems. Their rapid variability on a variety of time scales (e.g. from a few seconds to decades) allow us to study and understand their long and short time scales variabilities which are directly linked to the variation in mass transfer from the companion star to the WD. For CVs which contain an accretion disc, e.g. dwarf novae and nova-likes, understanding the physics of accretion disc in these systems on short time scales directly gives us clues to understanding other astronomical objects with accretion discs such as active galactic nuclei and tidal disruption events. On the other hand, CVs with strong magnetic fields, such as polars and intermediate polars, allow us to study the effects of magnetic fields on accreting WDs and also the physics of accretion onto these systems. In this project, students will engage in the comprehensive reduction and analysis of spectroscopic, photometric, and polarimetric observations of selected magnetic Cataclysmic Variables (mCVs), utilising data collected from the South African Large Telescope (SALT) and the 1.9-m and 1.0-m telescopes at the South African Astronomical Observatory (SAAO). The candidate(s) will conduct an in-depth time-series analysis to scrutinise the dynamic nature of these systems. Moreover, the project involves the analysis of phase-resolved spectra, facilitating the creation of Doppler tomography maps. This process is crucial for delineating the diverse emission regions within the magnetic CVs, offering insights into their complex astrophysical processes.

Research Area:

Astronomy

Project Level:

Masters

This Project Is Offered At The Following Node(s):

(UCT)

Special Requirements:

Python coding and a good knowledge of the Linux environment. Attended the ACB MSc course.