Massive Galaxies in the Early Universe

This thesis seeks to better understand the formation and evolution of distant and massive galaxies. The light emitted from these galaxies has travelled 12 billion years to reach us, meaning we observe them close to their formation epochs in the early Universe. This thesis investigates the rarity of these galaxies using novel near-infrared imaging capabilities to efficiently and effectively identify them, and their physical properties by determining their kinematics to constrain their stellar masses. Understanding these galaxies' prevalence and physical properties can help us constrain galaxy formation and evolution processes that are often obscured by billions of years of evolution.