Compact groups in theory and practice - II. Comparing the observed and predicted nature of galaxies in compact groups

Abstract

We examine the properties of galaxies in compact groups identified in a mock galaxy catalogue based upon the Millennium Run simulation. The overall properties of groups identified in projection are in general agreement with the best available observational constraints. However, only ~30% of these simulated groups are found to be truly compact in 3 dimensions, suggesting that interlopers strongly affect our observed understanding of the properties of galaxies in compact groups. These simulations predict that genuine compact group galaxies are an extremely homogeneous population, confined nearly exclusively to the red sequence: they are best described as `red and dead' ellipticals. When interlopers are included, the population becomes much more heterogeneous, due to bluer, star-forming, gas-rich, late-type galaxies incorrectly identified as compact group members. These models suggest that selection of members by redshift, such that the line-of-sight velocity dispersion of the group is less than 1000 km/s, significantly reduces contamination to the 30% level. Selection of members by galaxy colour, a technique used frequently for galaxy clusters, is also predicted to dramatically reduce contamination rates for compact group studies.

15 pages, 9 figures, accepted for publication in MNRAS

References in corpus (46)

• Stellar population synthesis at the resolution of 2003
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• The many lives of active galactic nuclei: cooling flows, black holes and the luminosities and colours of galaxies
• Populating a cluster of galaxies - I. Results at z=0
• Galaxy Bimodality due to Cold Flows and Shock Heating
• The hierarchical formation of the brightest cluster galaxies
• Color Separation of Galaxy Types in the Sloan Digital Sky Survey Imaging Data
• Quantifying the bimodal color-magnitude distribution of galaxies
• Nearly 5000 Distant Early-Type Galaxies in COMBO-17: a Red Sequence and its Evolution since z~1
• Galaxy Luminosity Functions to z~1: DEEP2 vs. COMBO-17 and Implications for Red Galaxy Formation
• Evolution since z = 0.5 of the Morphology-Density relation for Clusters of Galaxies
• Clustering of Galaxies in a Hierarchical Universe: I. Methods and Results at z=0
• Galaxy bimodality versus stellar mass and environment
• Galaxy Star-Formation as a Function of Environment in the Early Data Release of the Sloan Digital Sky Survey
• The Broad-band Optical Properties of Galaxies with Redshifts 0.0 < z < 0.2
• The Star Formation Histories of Galaxies in Distant Clusters
• The 2dF Galaxy Redshift Survey: The environmental dependence of galaxy star formation rates near clusters
• The Nature of High-Redshift Galaxies
• Galaxy Pairs in the Sloan Digital Sky Survey I: Star Formation, AGN Fraction, and the Luminosity/Mass-Metallicity Relation
• The DEEP2 Galaxy Redshift Survey: The Galaxy Luminosity Function to z ~ 1
• The Red-Sequence Cluster Survey I: The Survey and Cluster Catalogs for Patches RCS0926+37 and RCS1327+29
• Ram pressure stripping the hot gaseous halos of galaxies in groups and clusters
• Tidally-Triggered Star Formation in Close Pairs of Galaxies
• Galaxy Pairs in the 2dF Survey I. Effects of Interactions in the Field
• Star Formation in Cluster Galaxies at 0.2<z<0.55
• The Influence of Environment on the Star Formation Rates of Galaxies
• A calibration of the relation between the abundance of close galaxy pairs and the rate of galaxy mergers
• Properties of Galaxy Groups in the SDSS: II.- AGN Feedback and Star Formation Truncation
• Star Formation in Close Pairs Selected from the Sloan Digital Sky Survey
• MoMaF : The Mock Map Facility
• H-alpha Photometry of Abell 2390
• Galaxy Pairs in the 2dFGRS II. Effects of interactions on star formation in groups and clusters
• A Survey of Faint Galaxy Pairs
• New Constraints on the Efficiencies of Ram-Pressure Stripping and the Tidal Disruption of Satellite Galaxies
• A Catalog of Compact Groups of Galaxies in the SDSS Commissioning Data
• A Study of Nine High-Redshift Clusters of Galaxies: IV. Photometry and Sp ectra of Clusters 1324+3011 and 1604+4321
• Luminosity dependence of the spatial and velocity distributions of galaxies: Semi-analytic models versus the Sloan Digital Sky Survey
• Evolution of Cluster and Field Ellipticals at $0.2<z<0.6$ in the CNOC Cluster Survey
• On the Influence of the Environment in the Star Formation Rates of a Sample of Galaxies in Nearby Compact Groups
• Tracking Down a Critical Halo Mass for Killing Galaxies through the Growth of the Red-Sequence
• A Hubble Space Telescope Snapshot Survey of Dynamically Close Galaxy Pairs in the CNOC2 Redshift Survey
• Compact groups in theory and practice - I. The spatial properties of compact groups
• Infrared Properties of Close Pairs of Galaxies
• The Influence of Interactions and Minor Mergers on the Structure of Galactic Disks: I.Observations and Disk Models
• The HI Content of Compact Groups of Galaxies
• The Association of Compact Groups of Galaxies with Large-scale Structures

Cited by in corpus (12)

• Galaxy Pairs in the Sloan Digital Sky Survey - II: The Effect of Environment on Interactions
• Compact groups in theory and practice - III. Compact groups of galaxies in the Sixth Data Release of the Sloan Digital Sky Survey
• The Dynamics of Galaxy Pairs in a Cosmological Setting
• Comparing galaxy populations in compact and loose groups of galaxies
• Galaxy and Mass Assembly (GAMA): Demonstrating the power of WISE in the study of Galaxy Groups to $z<0.1$
• Compact groups in theory and practice -- IV. The connection to large-scale structure
• The Relation between Morphology and Dynamics of Poor Groups of Galaxies
• Compact Groups of Galaxies in Sloan Digital Sky Survey and LAMOST Spectral Survey: I. The Catalogs
• Galaxy triplets in Sloan Digital Sky Survey Data Release 7: II. A connection with compact groups?
• On the nature of Small Galaxy Systems
• The Occurrence of Compact Groups of Galaxies Through Cosmic Time
• A Multiple Dry Merger at z=0.18: Witnessing The Assembly of a Massive Elliptical Galaxy