The Evolution of Mass-size Relation for Lyman Break Galaxies From z=1 to z=7

TL;DR

This study investigates how the stellar mass-size relation of star-forming Lyman-break galaxies evolves from redshift 7 to 1, revealing size growth over time consistent with galaxy formation models.

Contribution

First analysis of the mass-size relation evolution for Lyman-break galaxies from z~4 to z~7 using Hubble and Spitzer data, extending previous studies to higher redshifts.

Findings

The mass-size relation persists up to z~5.

Median galaxy sizes increase as redshift decreases.

Size evolution follows approximately (1+z)^{-1.2} for different mass ranges.

Abstract

For the first time, we study the evolution of the stellar mass-size relation for star-forming galaxies from z ~ 4 to z ~ 7 from Hubble-WFC3/IR camera observations of the HUDF and Early Release Science (ERS) field. The sizes are measured by determining the best fit model to galaxy images in the rest-frame 2100 \AA \ with the stellar masses estimated from SED fitting to rest-frame optical (from Spitzer/IRAC) and UV fluxes. We show that the stellar mass-size relation of Lyman-break galaxies (LBGs) persists, at least to z ~ 5, and the median size of LBGs at a given stellar mass increases towards lower redshifts. For galaxies with stellar masses of 9.5<Log(M*/Msun)<10.4 sizes evolve as $(1+z)^{-1.20\pm0.11}$. This evolution is very similar for galaxies with lower stellar masses of 8.6<Log(M*/Msun)<9.5 which is $r_{e} \propto (1+z)^{-1.18\pm0.10}$, in agreement with simple theoretical galaxy formation models at high z. Our results are consistent with previous measurements of the LBGs mass-size relation at lower redshifts (z ~ 1-3).