The Evolving Relations Between Size, Mass, Surface Density, and Star Formation in 3 × 10⁴ Galaxies Since z = 2

TY - JOUR

T1 - The Evolving Relations Between Size, Mass, Surface Density, and Star Formation in 3 × 104 Galaxies Since z = 2

AU - Williams, R. J.

AU - Quadri, R. F.

AU - Franx, M.

AU - van Dokkum, P.

AU - Kriek, M.

AU - Labbe, I

AU - Toft, Sune

PY - 2010/4/20

Y1 - 2010/4/20

N2 - The presence of massive, compact, quiescent galaxies at z>2 presents a major challenge for theoretical models of galaxy formation and evolution. Using one of the deepest large public near-IR surveys to date, we investigate in detail the correlations between star formation and galaxy structural parameters (size, stellar mass, and surface density) from z = 2 to the present. At all redshifts, massive quiescent galaxies (i.e., those with little or no star formation) occupy the extreme high end of the surface density distribution and follow a tight mass-size correlation, while star-forming galaxies show a broad range of both densities and sizes. Conversely, galaxies with the highest surface densities comprise a nearly homogeneous population with little or no ongoing star formation, while less dense galaxies exhibit high star formation rates and varying levels of dust obscuration. Both the sizes and surface densities of quiescent galaxies evolve strongly from z = 2-0; we parameterize this evolution for both populations with simple power-law functions and present best-fit parameters for comparison to future theoretical models. Higher-mass quiescent galaxies undergo faster structural evolution, consistent with previous results. Interestingly, star-forming galaxies' sizes and densities evolve at rates similar to those of quiescent galaxies. It is therefore possible that the same physical processes drive the structural evolution of both populations, suggesting that "dry mergers" may not be the sole culprit in this size evolution.

AB - The presence of massive, compact, quiescent galaxies at z>2 presents a major challenge for theoretical models of galaxy formation and evolution. Using one of the deepest large public near-IR surveys to date, we investigate in detail the correlations between star formation and galaxy structural parameters (size, stellar mass, and surface density) from z = 2 to the present. At all redshifts, massive quiescent galaxies (i.e., those with little or no star formation) occupy the extreme high end of the surface density distribution and follow a tight mass-size correlation, while star-forming galaxies show a broad range of both densities and sizes. Conversely, galaxies with the highest surface densities comprise a nearly homogeneous population with little or no ongoing star formation, while less dense galaxies exhibit high star formation rates and varying levels of dust obscuration. Both the sizes and surface densities of quiescent galaxies evolve strongly from z = 2-0; we parameterize this evolution for both populations with simple power-law functions and present best-fit parameters for comparison to future theoretical models. Higher-mass quiescent galaxies undergo faster structural evolution, consistent with previous results. Interestingly, star-forming galaxies' sizes and densities evolve at rates similar to those of quiescent galaxies. It is therefore possible that the same physical processes drive the structural evolution of both populations, suggesting that "dry mergers" may not be the sole culprit in this size evolution.

U2 - 10.1088/0004-637X/713/2/738

DO - 10.1088/0004-637X/713/2/738

M3 - Journal article

SN - 0004-637X

VL - 713

SP - 738

EP - 750

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

ER -