Galaxy groups in the 2dF galaxy redshift survey: A Compactness Analysis of Groups

Abstract

A comprehensive study on compactness has been carried out on the 2dF Galaxy Group Catalogue constructed by Merchán & Zandivarez. The compactness indexes defined in this work take into account different geometrical constraints in order to explore a wide range of possibilities. Our results show that there is no clear distinction between groups with high and low level of compactness when considering particular properties as the radial velocity dispersion, the relative fraction of galaxies per spectral type and luminosity functions of their galaxy members. Studying the trend of the fraction of galaxies per spectral type as a function of the dimensionless crossing time some signs of dynamical evolution are observed. From the comparison with previous works on compactness we realize that special care should be taken into account for some compactness criteria definitions in order to avoid possible biases in the identification.

11 pages, 14 figures, resubmitted to MNRAS after minor revision

References in corpus (17)

• The 2dF Galaxy Redshift Survey: Spectra and redshifts
• The SuperCOSMOS Sky Survey. Paper I: Introduction and Description
• The Properties of Poor Groups of Galaxies: I. Spectroscopic Survey and Results
• The 2dF Galaxy Redshift Survey: The b_J-band galaxy luminosity function and survey selection function
• The 2dF Galaxy Redshift Survey: Luminosity dependence of galaxy clustering
• The 2dF Galaxy Redshift Survey: Galaxy luminosity functions per spectral type
• Compact groups of galaxies
• Galaxy groups in the 2dF redshift survey: The catalogue
• Compact Group Selection From Redshift Surveys
• Estimating Galaxy Luminosity Functions
• Are X-ray properties of loose groups different from those of compact groups?
• Compact groups in the UZC galaxy sample
• Galaxy groups in the 2dF redshift survey: Effects of Environment on Star Formation
• Galaxy groups in the 2dF redshift survey: Galaxy Spectral Type Segregation in Groups
• Galaxy groups in the 2dF galaxy redshift survey: Luminosity and Mass Statistics
• Environments of Redshift Survey Compact Groups of Galaxies
• Deep Optical Observations of Compact Groups of Galaxies

Cited by in corpus (5)

• Galaxy groups in the 2dF galaxy redshift survey: Large Scale Structure with Groups
• Compact Groups in the UZC galaxy sample: II. Connections between morphology, luminosity and large-scale density
• Improving Hickson-like compact group finders in redshift surveys: an implementation in the SDSS
• Compact groups of galaxies in GAMA -- Probing the densest minor systems at intermediate redshifts
• The $-12$ mag dip in the galaxy luminosity function of Hickson Compact Groups