Hernandez Santisteban, Juan (2016) Multi-wavelength observations of accreting compact objects. University of Southampton, Faculty of Physical Science and Engineering, Doctoral Thesis, 135pp.
Abstract
The study of compact binaries invokes core astrophysical concepts ranging from stellar and sub-stellar atmospheres and interiors, stellar and binary evolution to physics of accretion. All of these systems are hosts to a compact object a white dwarf,neutron star or black hole - which produces a wide variety of exotic and energetic phenomena across the full electromagnetic spectrum. In this thesis, I will make use of multi-wavelength observations ranging from far-ultraviolet to near-infrared in order to investigate two main topics: a) the late evolution of cataclysmic variables, and b) the accreting state of transitional millisecond pulsars.
Firstly, I analyse the Very Large Telescope X-Shooter time-resolved spectroscopy of the short orbital period cataclysmic variable, SDSS J1433+1011,in Chapter 2. The wide wavelength coverage allowed me to perform a detailed characterisation of the system, as well as a direct mass measurement of the brown dwarf companion. I show that the donor in SDSS J1433+1011 successfully transitioned from the stellar to sub-stellar regime, as predicted by evolutionary models. Further light-curve modelling allowed me to show that allow albedo as well as a low heat circulation efficiency is present in the atmosphere of the sub-stellar donor. In Chapter 3, I analyse data from large synoptic surveys, such as SDSS and PTF, to search for the predicted population of dead cataclysmic variables. Following the non-detection of dead CVs, I was able to estimate the space density (p0 < 2 x 10-5 pc-3) of this hidden population via a Monte Carlo simulation of the Galactic CV population. In Chapter 4, I present Hubble Space Telescope ultraviolet observations of the transitional millisecond pulsar PSR J1023+0038, during its latest accretion state. In combination with optical and near-infrared data, I show that a standard accretion disc does not reach the magnetosphere of the neutron star. Instead,the overall spectrum is consistent with a truncated disc at ∼ 2:3 x 109 cm away from the compact object. Furthermore, the ultraviolet data shares remarkable similarities with the only accreting white dwarf in a propeller regime, AE Aqr. Finally, I summarise my results in Chapter 5 and provide future lines of research in accreting compact binaries based on this work.
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- Faculties (pre 2018 reorg) > Faculty of Physical Sciences and Engineering (pre 2018 reorg) > Physics & Astronomy (pre 2018 reorg) > Astronomy Group (pre 2018 reorg)
Current Faculties > Faculty of Engineering and Physical Sciences > School of Physics and Astronomy > Physics & Astronomy (pre 2018 reorg) > Astronomy Group (pre 2018 reorg)
School of Physics and Astronomy > Physics & Astronomy (pre 2018 reorg) > Astronomy Group (pre 2018 reorg) - Faculties (pre 2018 reorg) > Faculty of Physical Sciences and Engineering (pre 2018 reorg) > Physics & Astronomy (pre 2018 reorg)
Current Faculties > Faculty of Engineering and Physical Sciences > School of Physics and Astronomy > Physics & Astronomy (pre 2018 reorg)
School of Physics and Astronomy > Physics & Astronomy (pre 2018 reorg)
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