This thesis describes an investigation of high-energy accretion in stellar-mass black holes and neutron stars using radio and X-ray observations. In particular, two of the largest Galactic X-ray binaries, with black hole masses of rv 10 M0 were examined in detail: GRS 1915+105 and Cygnus X-I. Observations were taken with radio interferometers at frequencies between 1.4 and 15 GHz. These were compared with X-ray observations made between 2 to 12 keY, taken with instrumentation on-board spacecraft in near Earth orbit. Technical developments in data transport have proved the feasibility of using the internet to transfer real-time astronomical data at gigabits per second. A proof-of-concept experiment described here, has shown that it is possible to make rapid e-VLBI observations of transient sources such as Galactic X-ray binaries. The first e-VLBI observations of GRS 1915+105 were made with the e-EVN immediately showing the inner structure of the steady jet. 'Adaptive e-VLBI' successfully proved the use of this technique to take snap shots of the inner region to then schedule further observations. A long series of MERLIN observations of GRS 1915+105 at 1.4 and 1.6 GHz are presented showing differences in the large-scale structure (> 50 mas) during various X-ray states. Polarisation measurements were also taken showing de-polarisation in the inner core during the ejection of a superluminal knot. Results have shown that the change in X-ray spectral hardness, from hard to soft, immediately coincided with the ejection of a superluminal knot; however, observations have shown no large-scale extended structure, during the so-called 'plateau' state, despite this being the strongest radio state. Only a steady jet with a flat spectrat index is observed at angular scales of less than 10 mas. Monitoring with the Ryle Telescope has then shown this steady jet to be present for periods of about 5 to 60 days every 1.3 years.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:505413 |
| Date | January 2009 |
| Creators | Rushton, Anthony P. |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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