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dc.contributor.advisorZhao, Hongsheng
dc.contributor.authorHodson, Alistair
dc.coverage.spatialxxiii, 167, [7] p.en_US
dc.description.abstractThis thesis attempts to test several frameworks of non-Newtonian gravity in the context of galaxies and galaxy clusters. The theory most extensively discussed was that of Modified Newtonian Dynamics (MOND) with Galileon gravity, Emergent Gravity (EG) and Modified Gravity (MOG) mentioned to a lesser extent. Specifically, the main focus of this thesis was to determine whether MOND and MOND-like theories were compatible with galaxy cluster data, without the need to include cold dark matter. To do this, the paradigms of Extended MOND (EMOND), Generalised MOND (GMOND) and superfluid dark matter were investigated. The theories were outlined and applied to galaxy cluster data. The main findings of this were that EMOND and GMOND had some success with explaining galaxy cluster mass profiles, without requiring an additional dark matter component. The superfluid paradigm also enjoyed some success in galaxy clusters, which was expected as it behaves in a similar manner to the standard cold dark matter paradigm in cluster environments. However, the superfluid paradigm may have issues in the very centre of galaxy clusters due to the theory predicting constant density cores, whereas the cold dark matter paradigm predicts density cores which are cuspier. The EMOND paradigm was also tested against ultra-diffuse galaxy (UDGs) data as they appear in cluster environments, where EMOND becomes important. It was found that EMOND can reproduce the inferred mass of the UDGs, assuming they lie on the fundamental manifold (FM). The validity of the assumptions used to model the UDGs are discussed in the text. A two-body problem was also conducted in the Galileon gravity framework. The amount of additional gravitational force, compared to Newtonian was determined for a small galaxy at the edge of a galaxy cluster.en_US
dc.publisherUniversity of St Andrews
dc.relationGeneralizing MOND to explain the missing mass in galaxy clusters - Alistair Hodson & Hongsheng Zhao - Accepted to Astronomy & Astrophyisics Journalen_US
dc.relationAre Over-massive Haloes of Ultra Diffuse Galaxies Consistent with Extended MOND? - Alistair Hodson & Hongsheng Zhao - Accepted to Astronomy & Astrophyisics Journalen_US
dc.relationGalaxy Clusters in the Context of Superfluid Dark Matter - Alistair Hodson, Hongsheng Zhao, Justin Khoury & Benoit Famaey - Accepted to Astronomy & Astrophyisics Journalen_US
dc.relationGalaxy Cluster A1689 in Modified MOND, MOG and Emergent Gravity - Alistair Hodson & Hongsheng Zhao - Not Yet accepteden_US
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International*
dc.subjectGalaxy dynamicsen_US
dc.subjectModified gravityen_US
dc.subjectGalaxy clustersen_US
dc.subject.lcshCosmology--Mathematical modelsen
dc.titleA non-Newtonian perspective of gravity : testing modified gravity theories in galaxies and galaxy clustersen_US
dc.contributor.sponsorScience and Technology Facilities Council (STFC)en_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US
dc.publisher.institutionThe University of St Andrewsen_US

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