Longterm lightcurves of X-ray binaries
Longterm lightcurves of X-ray binaries
The X-ray binaries (XRB) consist of a compact object and a stellar companion, which undergoes large-scale mass-loss to the compact object by virtue of the tight (Porb usually hours-days) orbit, producing an accretion disk surrounding the compact object. The liberation of gravitational potential energy powers exotic high-energy phenomena; indeed the resulting accretion/outflow process is among the most efficient energy-conversion machines in the universe.
The Burst And Transient Source Experiment (BATSE) and RXTE All Sky Monitor (ASM) have provided remarkable X-ray lightcurves about 1.3keV for the entire sky, at near-continuous coverage, for intervals of 9 and 7 years respectively (with ˜ 3 years’ overlap). With an order of magnitude increase in sensitivity compared to previous survey instruments, these instruments have provided new insight into the high-energy behaviour of XRBs on timescales of tens to thousands of binary orbits. This thesis describes detailed examination of the long-term X-ray lightcurves of the neutron star XRB X2127+119, SMC X-1, Her X-1, LMC X-4, Cyg X-2 and the as yet unclassified Circinus X-1, and for Cir X-1, complementary observations in the IR band.
Chapters 1 and 2 introduce X-ray Binaries in general and longterm periodicities in particular. Chapter 3 introduces the longterm datasets around which this work is based, and the chosen methods of analysis of these datasets. Chapter 4 examines the burst history of the XRB X2127+119, suggesting three possible interpretations of the apparently contradictory X-ray emission from this system, including a possible confusion of two spatially distinct sources (which was later vindicated by high-resolution imaging). Chapters 5 and 6 describe the characterisation of accretion disk warping, providing observational verification of the prevailing theoretical framework for such disk-warps. Chapters 7 and 8 examine the enigmatic XRB Circinus X-1 with high-resolution IR spectroscopy (chapter 7) and the RXTE/ASM (chapter 8), establishing an improved orbital ephemeris and suggesting the system may be in a state of rapid post-supernova evolution. In chapter 8 we follow this up with a direct search for the X-ray supernova remnant expected from such a system, concluding that with present observations the diffuse emission from Cir-X-1 is indistinguishable from scattering by dust-grains in the interstellar medium.
University of Southampton
Clarkson, William
44dbf144-a802-4731-8c15-9b9b0f8df04f
2004
Clarkson, William
44dbf144-a802-4731-8c15-9b9b0f8df04f
Clarkson, William
(2004)
Longterm lightcurves of X-ray binaries.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The X-ray binaries (XRB) consist of a compact object and a stellar companion, which undergoes large-scale mass-loss to the compact object by virtue of the tight (Porb usually hours-days) orbit, producing an accretion disk surrounding the compact object. The liberation of gravitational potential energy powers exotic high-energy phenomena; indeed the resulting accretion/outflow process is among the most efficient energy-conversion machines in the universe.
The Burst And Transient Source Experiment (BATSE) and RXTE All Sky Monitor (ASM) have provided remarkable X-ray lightcurves about 1.3keV for the entire sky, at near-continuous coverage, for intervals of 9 and 7 years respectively (with ˜ 3 years’ overlap). With an order of magnitude increase in sensitivity compared to previous survey instruments, these instruments have provided new insight into the high-energy behaviour of XRBs on timescales of tens to thousands of binary orbits. This thesis describes detailed examination of the long-term X-ray lightcurves of the neutron star XRB X2127+119, SMC X-1, Her X-1, LMC X-4, Cyg X-2 and the as yet unclassified Circinus X-1, and for Cir X-1, complementary observations in the IR band.
Chapters 1 and 2 introduce X-ray Binaries in general and longterm periodicities in particular. Chapter 3 introduces the longterm datasets around which this work is based, and the chosen methods of analysis of these datasets. Chapter 4 examines the burst history of the XRB X2127+119, suggesting three possible interpretations of the apparently contradictory X-ray emission from this system, including a possible confusion of two spatially distinct sources (which was later vindicated by high-resolution imaging). Chapters 5 and 6 describe the characterisation of accretion disk warping, providing observational verification of the prevailing theoretical framework for such disk-warps. Chapters 7 and 8 examine the enigmatic XRB Circinus X-1 with high-resolution IR spectroscopy (chapter 7) and the RXTE/ASM (chapter 8), establishing an improved orbital ephemeris and suggesting the system may be in a state of rapid post-supernova evolution. In chapter 8 we follow this up with a direct search for the X-ray supernova remnant expected from such a system, concluding that with present observations the diffuse emission from Cir-X-1 is indistinguishable from scattering by dust-grains in the interstellar medium.
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Published date: 2004
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Local EPrints ID: 465316
URI: http://eprints.soton.ac.uk/id/eprint/465316
PURE UUID: b8718282-91fa-4a04-a357-70b735e6faf6
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Date deposited: 05 Jul 2022 00:37
Last modified: 16 Mar 2024 20:06
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Author:
William Clarkson
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