Compact groups from semi-analytical models of galaxy formation -- III: purity and completeness of Hickson-like catalogues

Abstract

Many catalogues of isolated compact groups of galaxies (CGs) have been extracted using Hickson's criteria to identify isolated, dense systems of galaxies, with at least three or four galaxies concordant in magnitude and redshift. But is not clear to what extent the catalogues of CGs are complete and reliable, relative to 3D truly isolated, dense groups. Using five different semi-analytical models of galaxy formation (SAMs), we identify isolated dense groups in 3D real space, containing at least three galaxies. We then build mock redshift space galaxy catalogues and run a Hickson-like CG finder. We find that the Hickson-like algorithm in redshift space is poor at recovering 3D CGs of at least 3 galaxies, with a purity of $\sim 10\%$ and a completeness of $\sim 22\%$. Among the $\sim 90\%$ of spurious systems, typically $60\%$ are dense structures that failed the 3D isolation criteria, while the remaining $40\%$ are chance alignments of galaxies along the line of sight, nearly all of which are within regular groups, with some variation with the SAM used for the analysis. In other words, while only $10\%$ of CGs are isolated dense groups, as intended, half are dense structures embedded within larger groups, and one-third are chance alignments within larger groups. The low completeness of the extracted CG sample is mainly due to the flux limits of the selection criteria. Our results suggest that a new observational algorithm to identify compact groups in redshift space is required to obtain dense isolated galaxy systems.

arXiv comment13 pages, 5 figures, 5 tables, accepted for publication in MNRAS

References in corpus (39)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Planck 2015 results. XIII. Cosmological parameters
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• The hierarchical formation of the brightest cluster galaxies
• From dwarf spheroidals to cDs: Simulating the galaxy population in a LCDM cosmology
• Galaxy formation in the Planck Cosmology - I. Matching the observed evolution of star formation rates, colours and stellar masses
• Galaxy groups in the 2dFGRS: the group-finding algorithm and the 2PIGG catalogue
• Percolation Galaxy Groups and Clusters in the SDSS Redshift Survey: Identification, Catalogs, and the Multiplicity Function
• Galaxy formation in WMAP1 and WMAP7 cosmologies
• Dark matter and visible baryons in M33
• One simulation to fit them all - changing the background parameters of a cosmological N-body simulation
• Imprints of dark energy on cosmic structure formation: II) Non-Universality of the halo mass function
• Constraining dark energy from the abundance of weak gravitational lenses
• L-GALAXIES 2020: Spatially resolved cold gas phases, star formation and chemical enrichment in galactic discs
• Compact Group Selection From Redshift Surveys
• Compact groups in theory and practice - III. Compact groups of galaxies in the Sixth Data Release of the Sloan Digital Sky Survey
• A Catalog of Compact Groups of Galaxies in the SDSS Commissioning Data
• Compact groups in the UZC galaxy sample
• Galaxy formation with L-GALAXIES: Modelling the environmental dependency of galaxy evolution and comparing with observations
• Compact Groups of Galaxies selected by stellar mass: The 2MASS Compact Group Catalogue
• Compact groups in theory and practice - I. The spatial properties of compact groups
• Compact groups from the Millennium Simulations: I. Their Nature and the completeness of the Hickson sample
• Where are compact groups in the local Universe?
• A Catalog of Distant Compact Groups Using DPOSS
• Compact groups in theory and practice -- IV. The connection to large-scale structure
• Compact Groups of Galaxies with Complete Spectroscopic Redshifts in the Local Universe
• Catalogs of Compact Groups of Galaxies from the Enhanced SDSS DR12
• Morphological evolution and galactic sizes in the L-Galaxies SA model
• Compact Groups of Galaxies in Sloan Digital Sky Survey and LAMOST Spectral Survey: I. The Catalogs
• Improving Hickson-like compact group finders in redshift surveys: an implementation in the SDSS
• Compact Groups of Galaxies in Sloan Digital Sky Survey and LAMOST Spectral Survey. II. Dynamical Properties of Isolated and Embedded Groups
• On the properties of compact groups identified in different photometric bands
• Compact groups from semi-analytical models of galaxy formation -- I: a comparative study of frequency and nature
• Compact groups from semi-analytical models of galaxy formation -- II: Different assembly channels
• Are compact groups hostile towards faint galaxies?
• The Occurrence of Compact Groups of Galaxies Through Cosmic Time
• Star-Forming Compact Groups (SFCGs): An ultraviolet search for a local sample

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