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Paper   IPM / Astronomy / 14762
School of Astronomy
1.  M. Mosleh
2.  S. Tacchella
3.  A. Renzini
4.  C. M. Carollo
5.  A. Molaeinezhad
6.  M. Onodera
7.  H. G. Khosroshahi
8.  S. Lilly
  Status:   Submitted
  Journal: ApJ
  Year:  2017
  Pages:   24
  Supported by:            ipm IPM
We study the history from zâ?¼2 to zâ?¼0 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 Mâ??>1010Mâ??, corrected for mass-to-light ratio (Mâ??/L) variations, and derive the half-mass radius (Rm), central stellar mass surface density within 1 kpc (Σ1) and surface density at Rm (Σm) 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 zâ?¼2 to zâ?¼0 by a factor of â?¼3â??5, whereas the half-mass sizes of star-forming galaxies increase only slightly, by a factor of â?¼2. The central densities Σ1 of quiescent galaxies decline slightly (by a factor of â?²1.7) from zâ?¼2 to zâ?¼0, while for star-forming galaxies Σ1 increases with time, at fixed mass. We show that the central density Σ1 has a tighter correlation with specific star-formation rate (sSFR) than Σm and for all masses and redshifts galaxies with higher central density are more prone to be quenched. Reaching a high central density (Σ1â?³1010Mâ??kpc2) seems to be a prerequisite for the cessation of star formation, though a causal link between high Σ1 and quenching is difficult to prove and their correlation can have a different origin.

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