Author ORCID Identifier

https://orcid.org/0000-0001-8178-8343

Date Available

6-16-2025

Year of Publication

2025

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy (PhD)

College

Arts and Sciences

Department/School/Program

Physics and Astronomy

Faculty

Yuanyuan Su

Abstract

Galaxy clusters form at the intersections of the cosmic web and carry imprints of the structure formation history of the universe. As massive, multi-component systems, they offer unique insights into the astrophysical processes that govern both structure formation and galaxy evolution. Observable across the full electromagnetic spectrum, clusters emit photons through a variety of mechanisms, each tracing different physical processes. This dissertation investigates both the thermodynamic and non-thermal properties of the intracluster medium (ICM) to better understand the physical processes shaping observed phenomena. It comprises three main studies, each targeting a different aspect of galaxy cluster physics. In the second chapter, I present a novel machine learning approach to estimate galaxy cluster masses directly from optical multi-band images. Cluster mass is a fundamental property that influences the evolution of member galaxies and plays a key role in cosmological studies. In the third chapter, I employ an autoencoder to identify the hidden signal of inverse Compton (IC) emission in galaxy clusters. Although IC emission remains undetected observationally, it is predicted by theory and supported indirectly by radio observations. Its detection would provide new insight into the relativistic electron populations within the ICM, offering a probe into the magnetic field in ICM. In the fourth chapter, I analyze XMM-Newton observations of an ancient sloshing cold front in the Virgo cluster to probe microphysical conditions in the ICM. Sloshing cold fronts are ubiquitous features in cool-core clusters like Virgo, offering valuable information about merger histories, thermodynamic structure, and the effectiveness of transport processes such as conduction and turbulence. Together, these studies demonstrate how galaxy clusters serve as laboratories for exploring both astrophysical and fundamental physical processes on cosmic scales.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2025.259

Funding Information

1. The first project was supported by Chandra X-ray Observatory grant GO1-22126X, NASA grant 80NSSC21K0714, and NSF grant 2107711 in 2022, 2023.

2. The second project was supported by the Smithsonian Institution, the Chandra High Resolution Camera Project through NASA contract NAS8-03060, and NASA Grants 80NSSC19K0116 and GO1-22132X in 2023, 2024.

3. The third project was supported by Chandra X-ray Observatory grant GO1- 22126X, NASA grant 80NSSC21K0714, and NSF grant 2107711 in year 2024, 2025.

4. Sheng-Chieh Lin was supported by the MacAdam Graduate Excellence Fellowship in Physics in 2022-2023.

Download

Share

COinS