The astrophysics of energetic x-ray binaries

Ogley, Richard Neil (1999). The astrophysics of energetic x-ray binaries. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000e219

Abstract

This thesis is a study of the X-ray binary Cygnus X-3, and related objects, using primarily observations at radio, sub-rom and infrared wavelengths. I find the emission mechanism to be synchrotron in the radio and sub-mm, while the infrared emission is thermal from the hot wind. The upper limit to the synchrotron emission is interpreted as being due to spectral ageing and implies a magnetic field strength of 7 T at a distance of 700 Rʘ from the centre of the system.

The nature of the companion star in Cyg X-3 was investigated by midinfrared observations using the ISO satellite. I find that the spectrum shows a steady decrease and flattening at longer wavelengths which is consist ant with a standard wind emission. Thus the complete quiescent spectrum from Cyg X-3 shows two different emission mechanisms and covers a full 5 decades of frequency.

High sensitivity and high time resolution radio photometry, taken during a minor flare period, reveal rapid (10 minute) increases and decreases in intensity which severely constrain the size of plasmons. Brightness temperatures of typically 10¹⁰K are found.

I also consider models for the superluminal expansion and contraction of the Cyg X-3 source, observed on a milli-arcsecond scale by LIewell et al. (1998). The elliptical shape and the superluminal contraction are particularly hard to explain. Models involving photon beams illuminating shells, or propagating photon patterns are the most plausible.

A thorough survey for maser emission from these sources has produced strong upper limits and improved our understanding of the circumstellar environment ofCyg X-3.

This thesis has probed the radio-jet X-ray binaries, and made significant advances, opening up more questions about the nature of these sources and new areas of research.