Forming Early-type Galaxies in Groups Prior to Cluster Assembly

Abstract

We study a unique proto-cluster of galaxies, the supergroup SG1120-1202. We quantify the degree to which morphological transformation of cluster galaxies occurs prior to cluster assembly in order to explain the observed early-type fractions in galaxy clusters at z=0. SG1120-1202 at z~0.37 is comprised of four gravitationally bound groups that are expected to coalesce into a single cluster by z=0. Using HST ACS observations, we compare the morphological fractions of the supergroup galaxies to those found in a range of environments. We find that the morphological fractions of early-type galaxies (~60 %) and the ratio of S0 to elliptical galaxies (0.5) in SG1120-1202 are very similar to clusters at comparable redshift, consistent with pre-processing in the group environment playing the dominant role in establishing the observed early-type fraction in galaxy clusters.

5 pages, 2 figures, 2 tables. Accepted for publication in ApJ Letters

References in corpus (27)

• Evolution since z = 0.5 of the Morphology-Density relation for Clusters of Galaxies
• Drizzle: A Method for the Linear Reconstruction of Undersampled Images
• Galaxy Star-Formation as a Function of Environment in the Early Data Release of the Sloan Digital Sky Survey
• The 2dF Galaxy Redshift Survey: The environmental dependence of galaxy star formation rates near clusters
• The Properties of Poor Groups of Galaxies: I. Spectroscopic Survey and Results
• The DEEP Groth Strip Survey II. Hubble Space Telescope Structural Parameters of Galaxies in the Groth Strip
• On the Survival and Destruction of Spiral Galaxies in Clusters
• The Morphology - Density Relation in z ~ 1 Clusters
• The evolution of the star formation activity in galaxies and its dependence on environment
• Environmental Dependence of Properties of Galaxies in the Sloan Digital Sky Survey
• A New Empirical Model for the Structural Analysis of Early-type Galaxies and a Critical Review of the Nuker Model
• Morphological evolution of disk galaxies in clusters
• The Transformation of Galaxies within the Large Scale Structure around a z=0.41 Cluster
• The Morphological Content of Ten EDisCS Clusters at 0.5 < z < 0.8
• The Galaxy Populations of X-Ray Detected, Poor Groups
• Mass-Selection and the Evolution of the Morphology-Density Relation from z=0.8 to z=0
• Evolution in the Color-Magnitude Relation of Early-Type Galaxies in Clusters of Galaxies at z~=1
• The morphology-density relation in X-ray bright galaxy groups
• Galaxy Groups at 0.3 <= z <= 0.55. II. Evolution to z ~ 0
• The Galaxy Population of Cluster RXJ0848+4453 at z=1.27
• Evidence for Cluster Evolution from an Improved Measurement of the Velocity Dispersion and Morphological Fraction of Cluster 1324+3011 at z = 0.76
• Galaxy Morphologies in the Cluster CL1358+62 at z=0.33
• X-ray Selected Intermediate-Redshift Groups of Galaxies
• The Evolution of Galaxies in X-ray Luminous Groups
• The Late Stellar Assembly of Massive Cluster Galaxies Via Major Merging
• Galaxy Cluster Assembly at z=0.37
• The Possible z=0.83 Precursors of z=0 M* Early-type Cluster Galaxies

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• The Atlas3D project - X. On the origin of the molecular and ionised gas in early-type galaxies
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• The Evolution of Central Group Galaxies in Hydrodynamical Simulations
• Mapping the Dark Side with DEIMOS: Globular Clusters, X-ray Gas, and Dark Matter in the NGC 1407 Group
• The Assembly of the Red Sequence at z~1: The Color and Spectral Properties of Galaxies in the Cl1604 Supercluster
• A Spectroscopically Confirmed Excess of 24 micron Sources in a Super Galaxy Group at z=0.37: Enhanced Dusty Star Formation Relative to the Cluster and Field Environment
• The Environmental Dependence of the Evolving S0 Fraction
• Evolution of the Early-Type Galaxy Fraction in Clusters since z = 0.8
• Tidal streams in newly discovered M32 analogues: evidence for the stripping scenario
• Preprocessing Among the Infalling Galaxy Population of EDisCS Clusters
• The fraction of early-type galaxies in low redshift groups and clusters of galaxies
• Formation, Evolution and Properties of Isolated Field Elliptical Galaxies
• Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902
• Evolution of galaxies in groups in the Coma Supercluster
• OMEGA - OSIRIS Mapping of Emission-line Galaxies in A901/2: III. - Galaxy Properties Across Projected Phase Space in A901/2
• Edge-on disk galaxies in the SDSS DR6: Fractions of bulgeless and other disk galaxies
• A Search for Young Stars in the S0 Galaxies of a Super-Group at z=0.37
• Pre-processing of Galaxies in the Early Stages of Cluster Formation in Abell 1882 at $z$=0.139
• The mass distribution in an assembling super galaxy group at $z=0.37$
• SG1120-1202: Mass-Quenching as Tracked by UV Emission in the Group Environment at z=0.37
• AMICO galaxy clusters in KiDS-DR3: the impact of estimator statistics on the luminosity-mass scaling relation
• Reconciling a significant hierarchical assembly of massive early-type galaxies at z<~1 with mass downsizing