We present the results of a size and structural analysis of 1395 galaxies at
0.5≤z≲8 with stellar masses log(M∗/M⊙)> 9.5 within the JWST Public CEERS field that overlaps with the HST CANDELS
EGS observations. We use GALFIT to fit single S\'ersic 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
∼(1+z)−0.71±0.19 up to z∼8. We discover that the vast
majority of massive galaxies at high redshifts have low S\'ersic 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∼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\'ersic index, varying little with mass. We
show that galaxies are more compact at redder wavelengths, independent of sSFR
or stellar mass up to z∼3. We demonstrate the size evolution of galaxies
continues up to z∼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 AGN
activity.Comment: Submitted to MNRA