Phase resolved spectral analysis of selected intermediate polars and the effect of warm absorbers in cataclysmic variables

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2014

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Pekön, Yakup

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In this study, XMM-Newton data of selected cataclysmic variables are examined. One of the sources is an Intermediate Polar (IP) EX Hya where the orbital and spin phase resolved spectra are analyzed in depth. A composite model is successfully fit to the spectra in order to explain the X-ray emission from the source. Changes in the emission, absorption and accretion behaviour of the system over the orbital and spin period of the system, as well as the changes in the system over two different epoch are determined for the first time with detailed phase resolution. The second source is another IP, FO Aqr. The behaviour of the spin pulse of the White Dwarf in the system was examined against the orbital modulation. Different absorption components in the system are able to be distinguished from each other. And most importantly, the presence of a warm absorber in the system was detected similar to that of LMXBs for the first time. We also study the orbital behaviour of X-rays for PQ Gem and V2069 Cyg which are IPs with soft emission components. Both systems show modulation in X-rays over the orbital period most possibly due to absorption from bulge on the disc. In PQ Gem, the absorption component from the disc is clearly separated with phase resolved spectral analysis. Lastly the classical novae V2491 Cyg and V4743 Sgr outburst data are investigated. As opposed to hot white dwarf stellar atmosphere models (expanding or stationary) previously suggested for modelling the X-ray outburst data, an ionizing emission continuum in tandem with collisionally ionized and photoionized absorber is utilized. The fits yield promising results explaining the temperatures of the underlying WD surface and absorption lines resulting from elements in the ejecta.

Subject Keywords

Stars, New., X-rays., Cataclysmic variable stars.

URI

http://etd.lib.metu.edu.tr/upload/12617768/index.pdf
https://hdl.handle.net/11511/23809

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

Y. Pekön, “Phase resolved spectral analysis of selected intermediate polars and the effect of warm absorbers in cataclysmic variables,” Ph.D. - Doctoral Program, Middle East Technical University, 2014.