Date of Award
Doctor of Philosophy (PhD)
Astrophysical & Planetary Sciences
Nils W. Halverson
J. Michael Shull
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.
Bender, Amy Nicole, "Galaxy Cluster Scaling Relations with APEX-SZ" (2011). Astrophysical & Planetary Sciences Graduate Theses & Dissertations. 12.