Surface brightness profiles of z=2 galaxies

We measure surface brightness profiles for these galaxies using a method that properly measures low surface brightness flux at large radii. We find that quiescent galaxies at z~2 very closely follow Sersic profiles, with n_median_=3.7, and have no excess flux at large radii.

Their effective radii are a factor of ~4 smaller than those of low-redshift quiescent galaxies of similar mass. However, there is a significant spread in sizes ({sigma}_log_10_r_e__=0.24), with the largest z~2 galaxies lying close to the z=0 mass-size relation. We compare the stellar mass surface density profiles with those of massive elliptical galaxies in the Virgo Cluster and confirm that most of the mass growth which occurs between z~2 and z=0 must be due to accretion of material onto the outer regions of the galaxies.