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dc.contributor.advisorMeintjes, P. J.
dc.contributor.authorVan Soelen, Brian
dc.date.accessioned2016-01-13T08:45:15Z
dc.date.available2016-01-13T08:45:15Z
dc.date.copyright2007-11-30
dc.date.issued2007-11-30
dc.date.submitted2007-11-30
dc.identifier.urihttp://hdl.handle.net/11660/2175
dc.description.abstractEnglish: LS 5039 is a high mass binary system that shows multi-wavelength broad non-thermal emission. It is also a very high energy gamma-ray emitter, with TeV energy gamma-rays detected by H.E.S.S. (High Energy Stereoscopic System). The nature of the compact object is unknown, but a mass > 1:44M is implied by the lack of an X-ray eclipse. The presence of radio jet-like structures and a proposed mass of 3:7M , under the assumption that the system is pseudosynchronized, has led to the system's classiffication as a microquasar. Another model, in terms of a pulsar wind has also been proposed for the system. This study undertakes a model independent investigation of LS 5039 (neither microquasar nor pulsar), to attempt to determine what conclusions can be drawn from the system from first principles. A brief review of certain aspects of high mass binary theory is first presented, including accretion, binary motion, non-thermal radiation and mass out ow processes. The analysis looks at thermal evaporation from a disc structure in a black hole system, showing that this is unlikely, given the required temperature and the lack of thermal emission observed. The required conversion efficiency > 20% of accretion power in the black hole scenario also suggests that an additional reservoir of power is needed. The presence of a rotating magnetized neutron star, provides not only the magnetic field required to produce the non-thermal emission, it also supplies an additional power source, i.e the rotational kinetic energy of the neutron star. The magnetic field strengths and electron energies (for single particles) required to produce the very high energy gamma-rays is considered. An analysis of a fast rotating magnetosphere suggests that the centrifugal force exerted on the wind material could prevent accretion in the system. The power for the system is then extracted by a turbulent MHD process near the Alfv en radius.en_US
dc.description.abstractAfrikaans: LS 5039 is 'n hoë massa binêre sisteem wat multi-golf engte nie-termiese uitstraling wys. Dit straal ook baie hoë energie gammastrale uit, met TeV energie gammastrale wat waargeneem is deur H.E.S.S. Die aard van die kompakte voorwerp is onbekend, maar 'n massa > 1:44M word geimpliseer deur die afwesigheid van 'n X-straal verduistering. Die teenwoordigheid van radio spuite en 'n voorgestelde massa van 3:7M, onder die aanname dat die sisteem pseudogesinkroniseerd is, het gelei tot 'n klassifikasie van 'n mikrokwasar sisteem. 'n Ander model, in terme van 'n vinnig roterende neutron ster, is ook voorgestel vir die sisteem. Hierdie studie bied 'n model-onafhanklike ondersoek van LS 5039, in 'n poging om te bepaal watter gevolgtrekkings van die sisteem gemaak kan word vanuit eerste beginsels. 'n Kort oorsig oor sekere aspekte van die hoë massa binêre teorie word eerste gebied, wat akkresie, binêre baanbeweging, nie-termiese radiasie en massa uitstroming prosesse insluit. Die analise wys dat termiese verdamping van 'n skyfstruktuur in 'n gravitasiekolk onwaarskynlik is, gegee die nodige temperatuur en die tekort aan termiese uitstraling. Die nodige omskakel doeltreffendheid > 20% van akkresie energie in die geval van 'n gravitasiekolk toon ook aan dat 'n addisionele energiebron nodig is. Die teenwoordigheid van 'n roterende gemagnetiseerde neutron ster verskaf nie slegs die magneetveld wat nodig is om die nie-termiese straling te produseer nie, maar dien ook as 'n addisionele energiebron, d.w.s die rotasionele kinetiese energie van die neutron ster. Die magnetiese veldsterktes en elektron energieë (vir enkel deeltjies) wat benodig word om die baie hoë energie gamma strale te produseer, word beskou. 'n Analise van 'n vinnig roterende magnetosfeer stel voor dat die sentrifugale effek wat op die wind materiaal uitgeoefen word, akkresie in die sisteem verhinder. Die drywing vir die sisteem is dan afkomstig van 'n turbulente MHD proses naby die Alfven radius.en_US
dc.language.isoenen_US
dc.publisherUniversity of the Free Stateen_US
dc.subjectDissertation (M.Sc. (Physics))--University of the Free State, 2007en_US
dc.subjectQuasarsen_US
dc.subjectBlack holes (Astronomy)en_US
dc.subjectX-ray binariesen_US
dc.subjectMagnetohydrodynamicsen_US
dc.subjectPropeller effecten_US
dc.subjectNon-thermal emissionen_US
dc.subjectBlack holeen_US
dc.subjectWind accretionen_US
dc.subjectNeutron staren_US
dc.subjectHigh mass x-ray binaryen_US
dc.subjectLS 5039en_US
dc.subjectMagnetohydrodynamicsen_US
dc.titleAn investigation into the nature of the relativistic compact object in the micro-quasar system LS 5039 : a multi-wavelength studyen_US
dc.typeDissertationen_US
dc.rights.holderUniversity of the Free Stateen_US


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