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postgraduate thesis: Survey of supersoft and quasisoft X-ray sources in the Magellanic Clouds with XMM-Newton and Chandra

TitleSurvey of supersoft and quasisoft X-ray sources in the Magellanic Clouds with XMM-Newton and Chandra
Authors
Issue Date2012
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Tsang, T. [曾梓豪]. (2012). Survey of supersoft and quasisoft X-ray sources in the Magellanic Clouds with XMM-Newton and Chandra. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4832944
AbstractSupersoft and quasisoft X-ray sources are collectively known as Very Soft X-ray Sources (VSSs) characterized by their considerably lower effective temperatures than normal X-ray emitting objects and the lack of significant emission above 1 keV, with measured temperatures ranging from about tens to less than about 300 eV, respectively. They are defined observationally and believed to be associated with a wide variety of astrophysical systems such as white dwarfs, neutron stars, and black holes. VSSs have been identified in our own Galaxy, the Magellanic Clouds, and other external galaxies. Due to the vicinity of the Magellanic Clouds and the low associated absorption of soft X-ray photons, they are unique in the studies of VSSs. However, no attempt has been made to search for VSSs and investigate the source population in the Magellanic Clouds using all the available archival data. A systematic survey of VSSs in the Magellanic Clouds was therefore performed using data from both XMM-Newton and Chandra. VSSs were identified by selection algorithim based on X-ray hardness ratio after the background galaxies and foreground stars were filtered. A total of 47 new supersoft and 75 new quasisoft candidates were identified. Six of them were strong enough for spectral analysis with derived temperatures of 15 – 250 eV and luminosities of of 3.5 ×?10?^34– 5.4 ×?10?^36 erg s^(-1). The softest and brightest candidate represents a promising supersoft candidate with a possible UV counterpart identified with XMM-Newton Optical Monitor having an estimated UV luminosity of ~2.7 ×?10?^35 erg s^(-1). The large dataset also allows the long-term studies of some of the previously identified supersoft X-ray sources. Through the comprehensive survey with multi-epoch data, an X-ray/UV stellar flare was discovered and its analysis is also reported.
DegreeMaster of Philosophy
SubjectMagellanic Clouds
X-ray astronomy
Dept/ProgramPhysics
Persistent Identifierhttp://hdl.handle.net/10722/193077

 

DC FieldValueLanguage
dc.contributor.authorTsang, Tsz-ho-
dc.contributor.author曾梓豪-
dc.date.accessioned2013-12-14T10:12:22Z-
dc.date.available2013-12-14T10:12:22Z-
dc.date.issued2012-
dc.identifier.citationTsang, T. [曾梓豪]. (2012). Survey of supersoft and quasisoft X-ray sources in the Magellanic Clouds with XMM-Newton and Chandra. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4832944-
dc.identifier.urihttp://hdl.handle.net/10722/193077-
dc.description.abstractSupersoft and quasisoft X-ray sources are collectively known as Very Soft X-ray Sources (VSSs) characterized by their considerably lower effective temperatures than normal X-ray emitting objects and the lack of significant emission above 1 keV, with measured temperatures ranging from about tens to less than about 300 eV, respectively. They are defined observationally and believed to be associated with a wide variety of astrophysical systems such as white dwarfs, neutron stars, and black holes. VSSs have been identified in our own Galaxy, the Magellanic Clouds, and other external galaxies. Due to the vicinity of the Magellanic Clouds and the low associated absorption of soft X-ray photons, they are unique in the studies of VSSs. However, no attempt has been made to search for VSSs and investigate the source population in the Magellanic Clouds using all the available archival data. A systematic survey of VSSs in the Magellanic Clouds was therefore performed using data from both XMM-Newton and Chandra. VSSs were identified by selection algorithim based on X-ray hardness ratio after the background galaxies and foreground stars were filtered. A total of 47 new supersoft and 75 new quasisoft candidates were identified. Six of them were strong enough for spectral analysis with derived temperatures of 15 – 250 eV and luminosities of of 3.5 ×?10?^34– 5.4 ×?10?^36 erg s^(-1). The softest and brightest candidate represents a promising supersoft candidate with a possible UV counterpart identified with XMM-Newton Optical Monitor having an estimated UV luminosity of ~2.7 ×?10?^35 erg s^(-1). The large dataset also allows the long-term studies of some of the previously identified supersoft X-ray sources. Through the comprehensive survey with multi-epoch data, an X-ray/UV stellar flare was discovered and its analysis is also reported.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.subject.lcshMagellanic Clouds-
dc.subject.lcshX-ray astronomy-
dc.titleSurvey of supersoft and quasisoft X-ray sources in the Magellanic Clouds with XMM-Newton and Chandra-
dc.typePG_Thesis-
dc.identifier.hkulb4832944-
dc.description.thesisnameMaster of Philosophy-
dc.description.thesislevelMaster-
dc.description.thesisdisciplinePhysics-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b4832944-
dc.date.hkucongregation2012-

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