Date of Award

8-2014

Level of Access

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

Advisor

David Batuski

Second Committee Member

Neil Comins

Third Committee Member

James McClymer

Abstract

Observations of the Universe on the largest scales have revealed a breathtaking and vast filamentary structure, with dense superclusters of galaxies connected by lower density sheets and filaments, surrounding large voids that are almost completely devoid of luminous matter. The superclusters of galaxies, which are the largest structures in the Universe, are generally not sufficiently dense to be gravitationally bound, and they therefore expand with the Universe. However, in recent decades it has been suggested that there should exist a small number of superclusters with sufficient matter density to be gravitationally bound. To date only one such structure, the Shapley Supercluster, has ever been confirmed, but several other candidate bound superclusters have been identified.

I present a dynamical analysis of three candidate bound superclusters of galaxies; The Corona Borealis Supercluster (CSC), the Aquarius Supercluster (ASC), and the Microscopium Supercluster (MSC). Two galaxy scaling relations, the Fundamental Plane and the Kormendy Relation, are used to make redshift independent distance determinations to each of the clusters in the densest region of each supercluster. The inter-cluster dynamics are assessed by comparing these distances with spectroscopic redshifts. If the clusters are strongly interacting gravitationally, as will be the case if the supercluster is bound, then the redshift of each cluster will include both the recession velocity due to the expansion of the Universe, and the peculiar velocity due to the gravitational interactions. The peculiar velocity components are isolated in this study, and used to infer the current dynamical state of each supercluster. High quality data from the Sloan Digital Sky Survey are used for analysis of the CSC, and allow for an accurate assessment of the dynamics that clearly indicates extended bound structure. Extensive comparisons with simulations and analytical models convincingly demonstrate that the CSC is a bound supercluster. Data for both the MSC and ASC come from an observing program designed for the purpose, and are of sufficient quality to allow for a preliminary analysis of the dynamical state of each structure. These analyses indicate that both superclusters may be bound, and a more detailed analysis is warranted.

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