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dc.contributor.authorChequers, Matthew
dc.contributor.otherQueen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.))en
dc.date.accessioned2018-07-23T19:11:19Z
dc.date.available2018-07-23T19:11:19Z
dc.identifier.urihttp://hdl.handle.net/1974/24409
dc.description.abstractIn this thesis we study the dynamics of vertical (bending) waves in Milky Way-like disc galaxies. The main goals of the thesis are to form a coherent picture for the formation and evolution of bending waves using three-dimensional $N$-body simulations, develop tools and machinery to aid in the study of vertical waves in both simulations and astrometric surveys, and to make predictions for what we might see in the analysis of Gaia data. The hallmark simulations presented in this thesis evolve a two-component disc embedded in smooth and `clumpy' haloes, where the latter contains multiple orbiting substructure. One of our main conclusions is that vertical (bending) waves should be generic, long-lived features of massive discs that can form with and without provocation from external agents, though the predominant type of vertical wave induced by the latter is dependent on the perturber's orbital parameters. Furthermore, we find that bending is a property almost exclusive to kinematically cooler (thin disc) stellar populations. In our simulations bending waves manifest as variations in mean vertical displacement and bulk vertical motions, that together behave largely as simple monochromatic plane waves. At intermediate radii they appear as tightly wound, short-wave corrugations that match smoothly onto the warp near the edge of the disc. By way of Fourier and spectral analyses, based on classical studies of in-plane density waves and further developed in this thesis for the study of vertical waves, we find that in general the waves are a superposition of modes that comprise two main branches on the radius-rotational frequency plane. The preeminent result of this thesis is a novel sequence of events describing the life-cycle of bending waves, which involves excitation, dispersion, phase-wrapping or shearing across the disc, self-gravitating wave-like action, and disc heating. This conclusion is largely borne out of the comparison between frequency power spectra of waves in our simulations with predictions from linear perturbation theory, and suggests that the wave-like features in astrometric surveys such as Gaia may indicate the existence of long-lived modes of a dynamically active disc in addition to perturbations from recent disc-satellite interactions.en_US
dc.language.isoenen_US
dc.relation.ispartofseriesCanadian thesesen
dc.rightsQueen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canadaen
dc.rightsProQuest PhD and Master's Theses International Dissemination Agreementen
dc.rightsIntellectual Property Guidelines at Queen's Universityen
dc.rightsCopying and Preserving Your Thesisen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectGalaxy dynamicsen_US
dc.subjectMilky Wayen_US
dc.subjectGaiaen_US
dc.subjectBending wavesen_US
dc.subjectDisc dynamicsen_US
dc.subjectVertical wavesen_US
dc.subjectN-body simulationsen_US
dc.subjectDisc galaxiesen_US
dc.titleRiding the waves: The formation and evolution of vertical bending waves in Milky Way-like disc galaxiesen_US
dc.typethesisen
dc.description.degreeDoctor of Philosophyen_US
dc.contributor.supervisorWidrow, Lawrence
dc.contributor.departmentPhysics, Engineering Physics and Astronomyen_US


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