Date of Award

2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

Committee Chair

Stephen A. Walker

Committee Member

Ming Sun

Committee Member

Max Bonamente

Committee Member

Richard Lieu

Research Advisor

Stephen A. Walker

Subject(s)

Galaxies--Clusters, X-ray astronomy

Abstract

We present the temperature, density, entropy, and pressure profiles of the intracluster mediums of eight galaxy clusters observed out to the virial radius with complete azimuthal coverage by the Suzaku X-ray space telescope. Suzaku’s low background was vital to probing the lower x-ray surface brightness of cluster outskirts that could not be studied by X-ray telescopes such as Chandra and XMM-Newton which have a higher background level. The eight clusters being examined are the last observed out to the virial radius by Suzaku that have not had their properties published. As all eight clusters have complete azimuthal coverage, we also studied the azimuthal variation of the properties mentioned above for all eight clusters by calculating the scatter of those properties. While examining these clusters, we compared our results to a previous compilation by Walker et al. (2019), which found an apparent correlation between the mass of clusters and an underestimation of entropy near the virial radius. Our results found that of five clusters with M[subscript 500] > 3×1014M⊙, four had entropy below the baseline profile, while two out of three lower mass clusters agree with the profile. We also analyzed previous studies and simulations of scatter in galaxy cluster outskirts, which appear to mostly match our results. Lastly, we searched for any evidence of the effect of filaments on the outskirts, but could not replicate the phenomena seen in previous papers.

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