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dc.contributor.advisorOozeer, N.
dc.contributor.advisorLoubser, S.I.
dc.contributor.authorWilson, Susan
dc.date.accessioned2016-01-11T12:04:06Z
dc.date.available2016-01-11T12:04:06Z
dc.date.issued2012
dc.identifier.urihttp://hdl.handle.net/10394/15822
dc.descriptionMSc (Space Physics), North-West University, Potchefstroom Campus, 2013en_US
dc.description.abstractIn this dissertation we aim to perform a multi-wavelength analysis of galaxy clusters. We discuss various methods for clustering in order to determine physical parameters of galaxy clusters required for this type of study. A selection of galaxy clusters was chosen from 4 papers, (Popesso et al. 2007b, Yoon et al. 2008, Loubser et al. 2008, Brownstein & Mo at 2006) and restricted by redshift and galactic latitude to reveal a sample of 40 galaxy clusters with 0.0 < z < 0.15. Data mining using Virtual Observatory (VO) and a literature survey provided some background information about each of the galaxy clusters in our sample with respect to optical, radio and X-ray data. Using the Kayes Mixture Model (KMM) and the Gaussian Mixing Model (GMM), we determine the most likely cluster member candidates for each source in our sample. We compare the results obtained to SIMBADs method of hierarchy. We show that the GMM provides a very robust method to determine member candidates but in order to ensure that the right candidates are chosen we apply a select choice of outlier tests to our sources. We determine a method based on a combination of GMM, the QQ Plot and the Rosner test that provides a robust and consistent method for determining galaxy cluster members. Comparison between calculated physical parameters; velocity dispersion, radius, mass and temperature, and values obtained from literature show that for the majority of our galaxy clusters agree within 3 range. Inconsistencies are thought to be due to dynamically active clusters that have substructure or are undergoing mergers, making galaxy member identi cation di cult. Six correlations between di erent physical parameters in the optical and X-ray wavelength were consistent with published results. Comparing the velocity dispersion with the X-ray temperature, we found a relation of T0:43 as compared to T0:5 obtained from Bird et al. (1995). X-ray luminosity temperature and X-ray luminosity velocity dispersion relations gave the results LX T2:44 and LX 2:40 which lie within the uncertainty of results given by Rozgacheva & Kuvshinova (2010). These results all suggest that our method for determining galaxy cluster members is efficient and application to higher redshift sources can be considered. Further studies on galaxy clusters with substructure must be performed in order to improve this method. In future work, the physical parameters obtained here will be further compared to X-ray and radio properties in order to determine a link between bent radio sources and the galaxy cluster environment.en_US
dc.language.isoenen_US
dc.publisherNorth-West University
dc.subjectGalaxy kinematics and dynamicsen_US
dc.subjectGalaxy Clustersen_US
dc.subjectStatistical analysisen_US
dc.subjectClustering algorithmsen_US
dc.subjectAbell clustersen_US
dc.subjectMass determinationen_US
dc.subjectMulti-wavelength viewen_US
dc.subjectKayes Mixing Modelen_US
dc.subjectGaussian Mixture Modelen_US
dc.subjectMulti-modalityen_US
dc.subjectRadio galaxiesen_US
dc.subjectData miningen_US
dc.subjectVelocity dispersionen_US
dc.subjectKernel density estimationen_US
dc.subjectOutlier detection techniquesen_US
dc.titleA multi-wavelength study of a sample of galaxy clustersen
dc.typeThesisen_US
dc.description.thesistypeMastersen_US
dc.contributor.researchID11290471 - Loubser, Susan Ilani (Supervisor)
dc.contributor.researchID24287717 - Oozeer, Nadeem (Supervisor)


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