The effects of environment on morphological evolution between 0<z<1.2 in the COSMOS Survey

Abstract

We explore the evolution of the morphology density relation using the COSMOS-ACS survey and previous cluster studies. The Gini parameter measured in a Petrosian aperture is found to be an effective way of selecting early-type galaxies free from systematic effects with redshift. We find galaxies are transformed from late (spiral and irregular) to early (E+S0) type galaxies more rapidly in dense than sparse regions. At a given density, the early-type fraction grows constantly with cosmic time, but the growth rate increases with density as a power law of index $0.29\pm 0.02$. However, at densities below 100 galaxies per Mpc${}^2$ no evolution is found at $z>0.4$. In contrast the star-formation-density relation shows strong evolution at all densities and redshifts, suggesting different physical mechanisms are responsible for the morphological and star formation transformation. We show photometric redshifts can measure local galaxy environment, but the present results are limited by photometric redshift error to densities above $\Sigma =3$ galaxies per Mpc${}^2$.

12 pages, 13 figures, to appear in the COSMOS special issue of the ApJS

References in corpus (5)

• The Gemini Deep Deep Survey: III. The abundance of massive galaxies 3-6 billion years after the Big Bang
• Large Structures and Galaxy Evolution in COSMOS at z < 1.1
• Photometric Redshifts of Galaxies in COSMOS
• The Cosmic Evolution Survey (COSMOS): a large-scale structure at z=0.73 and the relation of galaxy morphologies to local environment
• The angular correlations of galaxies in the COSMOS field

Cited by in corpus (21)

• The Cosmic Evolution Survey (COSMOS) -- Overview
• The Cosmic Evolution Survey (COSMOS): Subaru Observations of the HST COSMOS Field
• Large Structures and Galaxy Evolution in COSMOS at z < 1.1
• The Assembly of Galaxy Clusters
• The relation between star formation, morphology and local density in high redshift clusters and groups
• Photometric Redshifts of Galaxies in COSMOS
• The Role of Environment in the Mass-Metallicity Relation
• The Dependence of Galaxy Morphology and Structure on Environment and Stellar Mass
• The Evolution of the Field and Cluster Morphology-Density Relation for Mass-Selected Samples of Galaxies
• The evolution of early and late type galaxies in the COSMOS up to z~1.2
• The Cosmic Evolution Survey (COSMOS): a large-scale structure at z=0.73 and the relation of galaxy morphologies to local environment
• STAGES: the Space Telescope A901/2 Galaxy Evolution Survey
• Is the Gini coefficient a stable measure of galaxy structure?
• Kinematics and Stellar Populations of Low-Luminosity Early-Type Galaxies in the Abell 496 Cluster
• A Spectro-photometric Search for Galaxy Clusters in SDSS
• The [OII]3727 Luminosity function and Star Formation Rate at z~1.2 in the COSMOS 2 Square-degree Field and the Subaru Deep Field
• Relation Between Stellar Mass and Star Formation Activity in Galaxies
• Evidence for Morphology and Luminosity Transformation of Galaxies at High Redshifts
• Environmental Effects on the Star Formation Activity in Galaxies at z=1.2 in the COSMOS Field
• Classification of Extremely Red Objects in the Hubble Ultra Deep Field
• A Potential Galaxy Threshing System in the Cosmos Field