4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=10&confId=86">The Proceedings of SAIP2016</a> published on 24 December 2017

Probing accretion in magnetic Cataclysmic Variables through fast photometry

5 Jul 2016, 11:10
20m
5A (Kramer Law building)

5A

Kramer Law building

UCT Middle Campus Cape Town
Oral Presentation Track D1 - Astrophysics Astrophysics (1)

Speaker

Mr Hannes Breytenbach (University of Cape Town)

Please indicate whether<br>this abstract may be<br>published online<br>(Yes / No)

Yes

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD, N/A)?

PhD

Main supervisor (name and email)<br>and his / her institution

Dr. D.A.H. Buckley, dibnob@saao.ac.za, SALT

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

Yes

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

Accreting compact binary star systems are unique astrophysical laboratories. The presence of a mass transferring donor star, spilling material into the magnetosphere of a rotating compact companion, creates a fascinating variety of phenomena. In the case of the Intermediate Polars (IPs), the central white dwarf rotates asynchronously, usually in the presence of a truncated accretion disc. Fast (many frames per second) photometry offers a probe into the dynamics of the luminous material within these systems. Power density spectra of the variability in these systems can, for example, be used to estimate the radius of the inner accretion disc. In discless systems, the stronger magnetic field dictates the gas flow, entirely disrupting the formation of a disc, and often even enforcing synchronous rotation. Almost all the luminous radiation emanates from magnetically confined plasma in the accretion column that forms above the surface of the WD where this high velocity material impacts. A few of these systems display quasi-periodic oscillations (QPOs) in their optical brightness - a phenomenon still poorly understood, but intriguing in its potential to reveal details about the dynamics of plasma under such extreme conditions. In this talk I will present results from a recent observational campaign at SAAO to search for- and characterize QPOs in Polar type Cataclysmic variables, detailing some tantalizing new discoveries, while also discussing the shortfalls of our current theoretical understanding of this phenomenon.

Primary author

Mr Hannes Breytenbach (University of Cape Town)

Co-authors

Dr David Buckley (Southern African Large Telescope) Prof. Patrick Woudt (Department of Astronomy, University of Cape Town)

Presentation Materials

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