Connection between Stellar Mass Distributions within Galaxies and Quenching Since z = 2

Abstract

Abstract We study the history from to of the stellar mass assembly of quiescent and star-forming galaxies in a spatially resolved fashion. For this purpose, we use multi-wavelength imaging data from the Hubble Space Telescope (HST) over the GOODS fields and the Sloan Digital Sky Survey (SDSS) for the local population. We present the radial stellar mass surface density profiles of galaxies with , corrected for mass-to-light ratio ( /L) variations, and derive the half-mass-radius (R m ), central stellar mass surface density within 1 kpc ( ) and surface density at R m ( ) for star-forming and quiescent galaxies and study their evolution with redshift. At fixed stellar mass, the half-mass sizes of quiescent galaxies increase from to by a factor of , whereas the half-mass sizes of star-forming galaxies increase only slightly, by a factor of ∼2. The central densities of quiescent galaxies decline slightly (by a factor of ) from to , while for star-forming galaxies increases with time, at fixed mass. We show that the central density has a tighter correlation with specific star-formation rate (sSFR) than and for all masses and redshifts galaxies with higher central density are more prone to be quenched. Reaching a high central density ( ) seems to be a prerequisite for the cessation of star formation, though a causal link between high and quenching is difficult to prove and their correlation can have a different origin.