Star-forming galaxies at different epochs of the Universe, and those residing in a range of environments, exhibit significant variations in their physical properties and scaling relations, both among themselves and relative to quiescent galaxy populations. Connecting the evolutionary pathways followed by these populations is therefore crucial to understanding galaxy formation and evolution as a whole. In this thesis, we present an analysis of star-forming galaxies across ~11 billion years of cosmic history (0.2 Hubble Space Telescope grism spectroscopy, we determine the gas-phase metallicities of galaxies in the Quasar Sightline and Galaxy Evolution (QSAGE) survey. This analysis allowed us to determine the scaling relations between gas-phase metallicity, galaxy stellar mass and star formation rate to probe the chemical evolution of Cosmic Noon galaxies relative to those in the local Universe. In Chapter 3, we study the spatial distribution of star-forming galaxies in massive clusters at 0.206 JWST Emission Line Survey (JELS), the first survey to perform narrow-band rest-optical emission-line selection at this epoch. We use these narrow- and broad-band size measurements to determine the size--mass relation of star-forming galaxies at z=6.1. The novel narrow-band imaging from JELS enables a direct comparison between the spatial extent of active star formation and that of established stellar populations, providing new insights into galaxy assembly during the first major epoch of galaxy formation. Since both in-situ star formation and mergers play key roles in galaxy growth, we additionally perform a close-pair analysis to estimate the merger fraction at this epoch.
H M O Stephenson (Thu,) studied this question.