Evolution of the Size-Mass Relation of Star-forming Galaxies Since $z=5.5$ Revealed by CEERS

Abstract

We combine deep imaging data from the CEERS early release JWST survey and HST imaging from CANDELS to examine the size-mass relation of star-forming galaxies and the morphology-quenching relation at stellar masses ${\text{M}}_{\star }\ge 10^{9.5}{\text{M}}_{\odot }$ over the redshift range $0.5<z<5.5$. In this study with a sample of 2,450 galaxies, we separate star-forming and quiescent galaxies based on their star-formation activity and confirm that star-forming and quiescent galaxies have different morphologies out to $z=5.5$, extending the results of earlier studies out to higher redshifts. We find that star-forming and quiescent galaxies have typical Sérsic indices of $n\sim 1.3$ and $n\sim 4.3$, respectively. Focusing on star-forming galaxies, we find that the slope of the size-mass relation is nearly constant with redshift, as was found previously, but shows a modest increase at $z\sim 4.2$. The intercept in the size-mass relation declines out to $z=5.5$ at rates that are similar to what earlier studies found. The intrinsic scatter in the size-mass relation is relatively constant out to $z=5.5$.

20 pages, 8 figures, 1 table, submitted to ApJ