The Evolution of Mass-Size Relation for Lyman Break Galaxies from z = 1 to z = 7

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 field. The sizes are measured by determining the best-fit model to galaxy images in the rest-frame 2100 Å with the stellar masses estimated from spectral energy distribution 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 toward lower redshifts. For galaxies with stellar masses of 9.5 < log (M _*/M _⊙) < 10.4, sizes evolve as (1 + z)^{-1.20 ± 0.11}. This evolution is very similar for galaxies with lower stellar masses of 8.6 < log (M _*/M _⊙) < 9.5 which is r_e vprop(1 + z)^{-1.18 ± 0.10}, 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).