Hunting for cataclysmic variables using H[alpha] surveys
Hunting for cataclysmic variables using H[alpha] surveys
The IPHAS survey is currently observing the northern Galactic Plane in Hα, r', and i', and the work presented here focuses primarily on the effort to construct a new, large and well-defined sample of cataclysmic variables (CVs) from the survey.
I first investigate the properties of the known population of CVs in IPHAS. A selection algorithm has been developed to pick out objects from the IPHAS photometry that display a clear Hα excess. This has led to the recovery of ≃ 70 per cent of the known CVs as Hα emitters, roughly independent of CV type and orbital period. The selection algorithm has been employed further to create a catalogue of Hα excess objects, which is presented and analysed. The resulting catalogue contains 4869 Hα emitters.
A series of long-slit spectroscopic observing runs has so far provided identification spectra of several hundred Hα emitters. The majority are found to be early-type stars, whereas interacting binaries including CVs and symbiotic stars, make up a relatively small percentage of the emission line star population. Overall, this thesis shows that IPHAS is capable of discovering a significant sample of CVs that should be largely free of the selection effects that have plagued previous surveys. Once a significant population has been discovered, it will be possible to test theories of binary evolution and CV population synthesis models.
University of Southampton
2007
Witham, Andrew Robert
(2007)
Hunting for cataclysmic variables using H[alpha] surveys.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The IPHAS survey is currently observing the northern Galactic Plane in Hα, r', and i', and the work presented here focuses primarily on the effort to construct a new, large and well-defined sample of cataclysmic variables (CVs) from the survey.
I first investigate the properties of the known population of CVs in IPHAS. A selection algorithm has been developed to pick out objects from the IPHAS photometry that display a clear Hα excess. This has led to the recovery of ≃ 70 per cent of the known CVs as Hα emitters, roughly independent of CV type and orbital period. The selection algorithm has been employed further to create a catalogue of Hα excess objects, which is presented and analysed. The resulting catalogue contains 4869 Hα emitters.
A series of long-slit spectroscopic observing runs has so far provided identification spectra of several hundred Hα emitters. The majority are found to be early-type stars, whereas interacting binaries including CVs and symbiotic stars, make up a relatively small percentage of the emission line star population. Overall, this thesis shows that IPHAS is capable of discovering a significant sample of CVs that should be largely free of the selection effects that have plagued previous surveys. Once a significant population has been discovered, it will be possible to test theories of binary evolution and CV population synthesis models.
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Published date: 2007
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Local EPrints ID: 466332
URI: http://eprints.soton.ac.uk/id/eprint/466332
PURE UUID: b667c2da-0595-444c-a180-9775072c0654
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Date deposited: 05 Jul 2022 05:10
Last modified: 05 Jul 2022 05:10
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Author:
Andrew Robert Witham
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