{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/45397"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/45397","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Accretion- and nuclear-powered phenomena in neutron stars with millisecond spin periods","abstract":"\"Analysis of observations of the X-ray emission produced by accreting neutron stars with millisecond spin periods can provide important information about the masses M and radii R of neutron stars, thereby yielding uniquely valuable information about the still uncertain properties of cold matter at several times the density of nuclear matter; about the evolution of neutron star magnetic fields and spin rates; and about the physics of accretion onto these stars, which are found in close, low-mass binary star systems. Avenues for obtaining this information include modeling the accretion- and nuclear-powered millisecond X-ray brightness oscillations produced by some of these stars and the spectra of their nuclear-powered emission, and then comparing these models with high-quality X-ray data. In this thesis, I explore the so-called \"\"nearly aligned moving spot model\"\" that has been proposed to explain many of the observed properties of the accretion-powered millisecond X-ray brightness oscillations produced by some accreting neutron stars in close, low-mass binary star systems and compare the properties this model predicts with the observed properties of these stars. I also study the accuracy and precision with which M and R can be determined by analyzing energy-resolved waveforms of the X-ray brightness oscillations seen during some of the thermonuclear X-ray bursts produced by some of these neutron stars. Finally, I describe how comparison of high-precision measurements of X-ray burst spectra with the spectra predicted by high-precision model atmosphere calculations can be used to constrain M and R. I find that many observed properties of the accretion-powered millisecond X-ray oscillations can be successfully explained by a model in which the X-ray emitting areas on the neutron star surface are close to the star's rotation pole but wander. I find that M and R can be tightly constrained by analyzing energy-resolved X-ray burst oscillation waveform data measured by a future X-ray satellite instrument having 2-30 keV energy coverage and an effective area of 10 m^2, such as the proposed LOFT or AXTAR missions, provided the hot spots that produce these oscillations are not too far from the star's rotation equator. The precision of these M and R measurements can be increased substantially by independent knowledge of the inclination and other properties of the system. Finally, I find that the detailed model atmosphere spectra computed by Suleimanov et al. (2012) provide excellent descriptions of the most precise spectra of X-ray bursts that are currently available, verifying these models and potentially allowing M and R to be constrained using them. I explain the methodology used, describe the results, and discuss their implications.\"","abstract_html":""Analysis of observations of the X-ray emission produced by accreting neutron stars with millisecond spin periods can provide important information about the masses M and radii R of neutron stars, thereby yielding uniquely valuable information about the still uncertain properties of cold matter at several times the density of nuclear matter; about the evolution of neutron star magnetic fields and spin rates; and about the physics of accretion onto these stars, which are found in close, low-mass binary star systems. Avenues for obtaining this information include modeling the accretion- and nuclear-powered millisecond X-ray brightness oscillations produced by some of these stars and the spectra of their nuclear-powered emission, and then comparing these models with high-quality X-ray data. In this thesis, I explore the so-called ""nearly aligned moving spot model"" that has been proposed to explain many of the observed properties of the accretion-powered millisecond X-ray brightness oscillations produced by some accreting neutron stars in close, low-mass binary star systems and compare the properties this model predicts with the observed properties of these stars. I also study the accuracy and precision with which M and R can be determined by analyzing energy-resolved waveforms of the X-ray brightness oscillations seen during some of the thermonuclear X-ray bursts produced by some of these neutron stars. Finally, I describe how comparison of high-precision measurements of X-ray burst spectra with the spectra predicted by high-precision model atmosphere calculations can be used to constrain M and R. I find that many observed properties of the accretion-powered millisecond X-ray oscillations can be successfully explained by a model in which the X-ray emitting areas on the neutron star surface are close to the star's rotation pole but wander. I find that M and R can be tightly constrained by analyzing energy-resolved X-ray burst oscillation waveform data measured by a future X-ray satellite instrument having 2-30 keV energy coverage and an effective area of 10 m^2, such as the proposed LOFT or AXTAR missions, provided the hot spots that produce these oscillations are not too far from the star's rotation equator. The precision of these M and R measurements can be increased substantially by independent knowledge of the inclination and other properties of the system. Finally, I find that the detailed model atmosphere spectra computed by Suleimanov et al. (2012) provide excellent descriptions of the most precise spectra of X-ray bursts that are currently available, verifying these models and potentially allowing M and R to be constrained using them. I explain the methodology used, describe the results, and discuss their implications."","abstract_has_math":false,"creators":["Lo, Ka-Ho"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Lamb, Frederick K.","Stack, John D.","Fields, Brian D.","Thaler, Jonathan J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-08-22T16:38:59Z","date_published":"2013-08-22T16:38:59Z","updated_at":"2026-07-22T22:25:34Z","subjects":["neutron stars","dense matter","equation of state","bursts","millisecond pulsars","Large Observatory for X-ray Timing (LOFT)"],"languages":["en"],"rights":["Copyright 2013 Ka-Ho Lo"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/45397","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lamb, Frederick K.","Stack, John D.","Fields, Brian D.","Thaler, Jonathan J."]},{"key":"dc:creator","label":"Author","values":["Lo, Ka-Ho"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-08-22T16:38:59Z","2013-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["neutron stars","dense matter","equation of state","bursts","millisecond pulsars","Large Observatory for X-ray Timing (LOFT)"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2013 Ka-Ho Lo"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/45397"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["\"Analysis of observations of the X-ray emission produced by accreting neutron stars with millisecond spin periods can provide important information about the masses M and radii R of neutron stars, thereby yielding uniquely valuable information about the still uncertain properties of cold matter at several times the density of nuclear matter; about the evolution of neutron star magnetic fields and spin rates; and about the physics of accretion onto these stars, which are found in close, low-mass binary star systems. Avenues for obtaining this information include modeling the accretion- and nuclear-powered millisecond X-ray brightness oscillations produced by some of these stars and the spectra of their nuclear-powered emission, and then comparing these models with high-quality X-ray data. In this thesis, I explore the so-called \"\"nearly aligned moving spot model\"\" that has been proposed to explain many of the observed properties of the accretion-powered millisecond X-ray brightness oscillations produced by some accreting neutron stars in close, low-mass binary star systems and compare the properties this model predicts with the observed properties of these stars. I also study the accuracy and precision with which M and R can be determined by analyzing energy-resolved waveforms of the X-ray brightness oscillations seen during some of the thermonuclear X-ray bursts produced by some of these neutron stars. Finally, I describe how comparison of high-precision measurements of X-ray burst spectra with the spectra predicted by high-precision model atmosphere calculations can be used to constrain M and R. I find that many observed properties of the accretion-powered millisecond X-ray oscillations can be successfully explained by a model in which the X-ray emitting areas on the neutron star surface are close to the star's rotation pole but wander. I find that M and R can be tightly constrained by analyzing energy-resolved X-ray burst oscillation waveform data measured by a future X-ray satellite instrument having 2-30 keV energy coverage and an effective area of 10 m^2, such as the proposed LOFT or AXTAR missions, provided the hot spots that produce these oscillations are not too far from the star's rotation equator. The precision of these M and R measurements can be increased substantially by independent knowledge of the inclination and other properties of the system. Finally, I find that the detailed model atmosphere spectra computed by Suleimanov et al. (2012) provide excellent descriptions of the most precise spectra of X-ray bursts that are currently available, verifying these models and potentially allowing M and R to be constrained using them. I explain the methodology used, describe the results, and discuss their implications.\"","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-05-08T14:40:26Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Lo_Ka-Ho.pdf: 2324958 bytes, checksum: 78879743842ba7083cf8def153707c87 (MD5)","Made available in DSpace on 2013-08-22T16:38:59Z (GMT). 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Avenues for obtaining this information include modeling the accretion- and nuclear-powered millisecond X-ray brightness oscillations produced by some of these stars and the spectra of their nuclear-powered emission, and then comparing these models with high-quality X-ray data. In this thesis, I explore the so-called \"\"nearly aligned moving spot model\"\" that has been proposed to explain many of the observed properties of the accretion-powered millisecond X-ray brightness oscillations produced by some accreting neutron stars in close, low-mass binary star systems and compare the properties this model predicts with the observed properties of these stars. I also study the accuracy and precision with which M and R can be determined by analyzing energy-resolved waveforms of the X-ray brightness oscillations seen during some of the thermonuclear X-ray bursts produced by some of these neutron stars. Finally, I describe how comparison of high-precision measurements of X-ray burst spectra with the spectra predicted by high-precision model atmosphere calculations can be used to constrain M and R. I find that many observed properties of the accretion-powered millisecond X-ray oscillations can be successfully explained by a model in which the X-ray emitting areas on the neutron star surface are close to the star's rotation pole but wander. I find that M and R can be tightly constrained by analyzing energy-resolved X-ray burst oscillation waveform data measured by a future X-ray satellite instrument having 2-30 keV energy coverage and an effective area of 10 m^2, such as the proposed LOFT or AXTAR missions, provided the hot spots that produce these oscillations are not too far from the star's rotation equator. The precision of these M and R measurements can be increased substantially by independent knowledge of the inclination and other properties of the system. Finally, I find that the detailed model atmosphere spectra computed by Suleimanov et al. (2012) provide excellent descriptions of the most precise spectra of X-ray bursts that are currently available, verifying these models and potentially allowing M and R to be constrained using them. I explain the methodology used, describe the results, and discuss their implications.\"","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-05-08T14:40:26Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Lo_Ka-Ho.pdf: 2324958 bytes, checksum: 78879743842ba7083cf8def153707c87 (MD5)","Made available in DSpace on 2013-08-22T16:38:59Z (GMT). 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