EPOCHS VI: the size and shape evolution of galaxies since z 8 with JWST Observations

We present the results of a size and structural analysis of 1395 galaxies at 0.5 <= z less than or similar to 8 with stellar masses log (M-*/M-circle dot)> 9.5 within the James Webb Space Telescope Public CEERS field that overlaps with the Hubble Space Telescope Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey EGS observations. We use GALFIT to fit single S & eacute;rsic models to the rest-frame optical profile of our galaxies, which is a mass-selected sample complete to our redshift and mass limit. Our primary result is that at fixed rest-frame wavelength and stellar mass, galaxies get progressively smaller, evolving as similar to(1 + z)(-0.71 +/- 0.19) up to z similar to 8. We discover that the vast majority of massive galaxies at high redshifts have low S & eacute;rsic indices, thus do not contain steep, concentrated light profiles. Additionally, we explore the evolution of the size-stellar mass relationship, finding a correlation such that more massive systems are larger up to z similar to 3. This relationship breaks down at z > 3, where we find that galaxies are of similar sizes, regardless of their star formation rates and S & eacute;rsic index, varying little with mass. We show that galaxies are more compact at redder wavelengths, independent of sSFR or stellar mass up to z similar to 3. We demonstrate the size evolution of galaxies continues up to z similar to 8, showing that the process or causes for this evolution is active at early times. We discuss these results in terms of ideas behind galaxy formation and evolution at early epochs, such as their importance in tracing processes driving size evolution, including minor mergers and active galactic nuclei activity.