Galaxy Cluster Scaling Relations with APEX-SZ

Bender, Amy Nicole

Graduate Thesis Or Dissertation

Galaxy Cluster Scaling Relations with APEX-SZ Public Deposited

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Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/nc580m71q

Abstract

Galaxy clusters are a unique laboratory that trace the formation and evolution of structure on the largest scales in the universe. In addition, clusters host an array of complex internal physical processes from star-formation and active galactic nuclei to turbulent gas motions. The ability to accurately estimate total cluster mass based on observable signals is a challenging but essential ingredient to use the full potential of clusters for precise cosmological constraints or studies of cluster astrophysics. In this dissertation, I present 152 GHz observations of galaxy clusters taken with the APEX- SZ imaging bolometer array. APEX-SZ is designed to image the small distortion in the Cosmic Microwave Background (CMB) due to the scattering of CMB photons off hot cluster electrons, known as the Sunyaev-Zel'dovich effect (SZE). A primary goal of APEX-SZ is to constrain power law scaling relations between the integrated SZE flux and cluster mass. I detail the extensive efforts taken to carefully clean and calibrate raw APEX-SZ data before parametrically modeling the sky signal, removing the effects of the instrumental response function in the final measurements. I explore and attempt to reduce the impact of potential systematic effects for each step in the data analysis process. I present scaling relations between SZE flux and X-ray temperature, a proxy for total mass, along with the maximum likelihood regression parameters for the full data set and several interesting subsets. I compare to expectations from theory and numerical simulations and find that the APEX- SZ scaling relations are consistent with the gravitationally-dominated self-similar model of cluster evolution. Additionally, I find that the SZE scaling relation is insensitive to the dynamical state of the cluster, although the associated intrinsic astrophysical scatter does increase between relaxed and disturbed clusters.

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