Irregular variability related to accretion discs in X-ray binaries
Irregular variability related to accretion discs in X-ray binaries
In this thesis I describe observational and analytical work on several X-ray binaries which are in quite different categories: X-ray transient, LMXBs, and HMXB X-ray pulsars. They all exhibit irregular variability in their X-ray and/or optical fluxes on time scales from seconds to months. In particular, with observations from both ground and space, we have found long-term variations in a number of luminous X-ray sources that cannot be orbital in nature. That these are present in such a wide variety of objects, indicates that must therefore be an inherent property of the accretion discs. 4U 1636-536 has been a persistent LMXB over at least ~ 40 years. However, it has been gradually declining in X-rays, whilst undergoing short outburst cycles. GX 339-4 is a black hole X-ray transient which has exhibited many outbursts in the last decades. I investigated the relationship between its X-ray flux and its optical counterpart during its previous X-ray outburst in 2002. Optical photometric and spectroscopic data were obtained to solve the LMC X-2’s binary dynamics and our optical data also show that the system has an unstable long term variation. SMC X-1 has shown a correlation between the quadratic fit to the pulse periods and the third period variation in the RXTE/ASM and CGRO/BATSE light curves. It is therefore very important to investigate this phenomenon further, as it is related to the physical interaction between the inner disc and pulsar.
University of Southampton
Shih, I Chun
e2906657-21ab-4615-a1c6-fb68c9375a31
2006
Shih, I Chun
e2906657-21ab-4615-a1c6-fb68c9375a31
Shih, I Chun
(2006)
Irregular variability related to accretion discs in X-ray binaries.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
In this thesis I describe observational and analytical work on several X-ray binaries which are in quite different categories: X-ray transient, LMXBs, and HMXB X-ray pulsars. They all exhibit irregular variability in their X-ray and/or optical fluxes on time scales from seconds to months. In particular, with observations from both ground and space, we have found long-term variations in a number of luminous X-ray sources that cannot be orbital in nature. That these are present in such a wide variety of objects, indicates that must therefore be an inherent property of the accretion discs. 4U 1636-536 has been a persistent LMXB over at least ~ 40 years. However, it has been gradually declining in X-rays, whilst undergoing short outburst cycles. GX 339-4 is a black hole X-ray transient which has exhibited many outbursts in the last decades. I investigated the relationship between its X-ray flux and its optical counterpart during its previous X-ray outburst in 2002. Optical photometric and spectroscopic data were obtained to solve the LMC X-2’s binary dynamics and our optical data also show that the system has an unstable long term variation. SMC X-1 has shown a correlation between the quadratic fit to the pulse periods and the third period variation in the RXTE/ASM and CGRO/BATSE light curves. It is therefore very important to investigate this phenomenon further, as it is related to the physical interaction between the inner disc and pulsar.
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Published date: 2006
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Local EPrints ID: 466212
URI: http://eprints.soton.ac.uk/id/eprint/466212
PURE UUID: 0d47147a-6f4d-4041-b29a-cec7d5e05316
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Date deposited: 05 Jul 2022 04:47
Last modified: 05 Jul 2022 04:47
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Author:
I Chun Shih
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