Galaxy sizes in the early Universe

Abstract

We present preliminary results of a study of galaxy sizes at redshift $z\gtrsim 5$ using the high-resolution, zoom-in \textsc{FirstLight} simulations. We obtain a redshift-independent, chevron-shaped stellar mass--size relation with a peak at $M^{\star }\approx 10^{8.5}{\mathrm{M}}_{\odot }$. This relation is shaped by the individual evolution of galaxies, which undergo a phase of contraction at this mass scale triggered by a strong central starburst.

4 Pages, 2 figures