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Title: Multi-wavelength observations of cataclysmic variable stars
Author: Hickman, Richard D. G.
ISNI:       0000 0004 2709 3139
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2011
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Observations of the cataclysmic variable systems EX Dra, Z Cha, and OY Car using multi-wavelength data ranging from near-infrared to X-ray bands are presented and analysed. Obscuration of the white dwarf by intervening material is discussed in context of all three systems, including the confirmation of iron lines in the spectrum of OY Car and the absorbing nature of the accretion disc upon the soft X-ray band in Z Cha. Evidence for spiral shocks and slingshot prominences from the secondary star are found in EX Dra, while the extent of Z Cha's boundary layer is probed with extensive modelling of simultaneous optical and X-ray data. Combined with a spectral analysis, this leads to the conclusion of a truncated inner disc present within the system. The first radial velocity measurement of OY Car's red secondary star is presented, and used to produce a fully spectroscopic determination of the system's mass ratio which is compared to previous attempts using the photometric method. The second part of this thesis deals with the improvement of the Ultracam and Ultraspec instruments. For the former, increased colour precision is achieved by careful calibration of the instrument's filter response with respect to the SDSS system; a charge modulation problem is investigated and quantified; and the development of a software system designed to improve observation and reduction workflow is detailed. For Ultraspec, a careful analysis of the CCD parameters is performed in order to prepare the instrument for scientific quality data publication, including an analysis of spurious charge found present. It is also shown that the AC coupling of the video circuit in the CCD can cause erroneous values in the readout but can be rectified, and presence of charge trailing caused by electron traps is investigated with preliminary corrections shown.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QB Astronomy