The Relation Between Compact, Quiescent High Redshift Galaxies and Massive Nearby Elliptical Galaxies: Evidence for Hierarchical, Inside-Out Growth

Understand

Recent studies have shown that massive quiescent galaxies at high redshift are much more compact than present-day galaxies of the same mass.

• Here we compare the radial stellar density profiles and the number density of a sample of massive galaxies at z ~ 2.3 to nearby massive elliptical galaxies.
• We confirm that the average stellar densities of the z ~ 2.3 galaxies within the effective radius, rho(<r_e), are two orders of magnitude higher than those of local elliptical galaxies of the same stellar mass.
• However, we also find that the densities measured within a constant physical radius of 1 kpc, rho(<1 kpc), are higher by a factor of 2-3 only.