Dark-ages Reionization and Galaxy Formation Simulation -- XVII. Sizes, angular momenta and morphologies of high redshift galaxies

Understand

We study the sizes, angular momenta and morphologies of high-redshift galaxies using an update of the Meraxes semi-analytic galaxy evolution model.

• Our model successfully reproduces a range of observations from redshifts $z=0$-$10$.
• We find that the effective radius of a galaxy disc scales with UV luminosity as $R_e\propto L_{\textrm{UV}}^{0.33}$ at $z=5$-$10$, and with stellar mass as $R_e\propto M_\ast^{0.24}$ at $z=5$ but with a slope that increases at higher redshifts.
• Our model predicts that the median galaxy size scales with redshift as $R_e \propto (1+z)^{-m}$, where $m=1.98\pm0.07$ for galaxies with $(0.3$-$1)L^\ast_{z=3}$ and $m=2.15\pm0.05$ for galaxies with $(0.12$-$0.3)L^\ast_{z=3}$.