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EPOCHS Paper V. The dependence of galaxy formation on galaxy structure at z < 7 from JWST observations

A subset of the images of galaxies used in this work, the image cut-outs were derived using the pipeline, outlined and described in detail in (Ormerod et al., 2024). The images are ordered in increasing redshift from the top row downwards. The columns show an example of each morphology, in each redshift bin. (SF)/(P) denotes those that have been defined as star-forming/passive in the study of the main sequence. Each cut-out has a resolution of 0.03"" per pixel, and are constructed such that the background of each is scaled equally, for direct comparison. More examples are discussed and presented in Ferreira et al. (2023). Abstract: We measure the broad impact of galaxy structure on galaxy formation by examining the ongoing star formation and integrated star formation history as revealed through the stellar masses of galaxies at z<7 based on JWST CEERS data from the Extended Groth Strip (EGS). Using the morphological catalog of 3965 visually classified JWST galaxies from Ferreira et al. (2023), we investigate the evolution of stars, and when they form, as a function of morphological type as well as galaxies classified as passive and starburst through spectral energy distributions. Although disk galaxies dominate the structures of galaxies at z<7, we find that these disks are in general either 'passive', or on the main-sequence of star formation, and do not contain a large population of starburst galaxies. We also find no significant correlation between morphological type and the star formation rate or colours of galaxies at z < 7. In fact, we find that the morphologically classified 'spheroids' tend to be blue and are not found to be predominately passive systems at z > 1.5. We also find that the stellar mass function for disk galaxies does not evolve significantly during this time, whereas other galaxy types, such as the peculiar population, evolve dramatically, declining at lower redshifts. This indicates that massive peculiars are more common at higher redshifts. We further find that up to z~7, the specific star formation rate (sSFR) does not vary with visual morphology, but strongly depends on stellar mass and internal galaxy mass density. This demonstrates that at early epochs galaxy assembly is a mass-driven, rather than a morphologically-driven, process. Quenching of star formation is therefore a mass-dominated process throughout the universe's history, likely due to the presence of supermassive black holes.