Assessing the Accuracy of Masses and Spatial Correlations of Galaxy Groups

Abstract

Two algorithms for the identification of galaxy groups from redshift surveys are tested by application to simulated data derived from N-body simulation. The accuracy of the membership assignments by these algorithms is studied in a companion to this paper (Frederic 1994). Here we evaluate the accuracy of group mass estimates and the group-group correlation function. We find a strong bias to low values in the virial mass estimates of groups identified using the algorithm of Nolthenius \& White (1987). The Huchra \& Geller (1982) algorithm gives virial mass estimates which are correct on average. These two algorithms result in group catalogs with similar two-point correlations. We find that groups in a CDM model have excessively large mass to light ratios even when the group richness distribution agrees with observations. We also find that our CDM groups are more strongly correlated than individual halos (galaxies), unlike the groups in the CfA redshift survey extension.

20 pages + 3 figures, AASTeX, ApJS accepted. Compressed postscript figures available in ftp://arcturus.mit.edu/Preprints/grps2_figs.tar. CSR-94-21

Cited by in corpus (15)

• Groups of Galaxies in the Two Micron All-Sky Redshift Survey
• Clustering of Galaxies in a Hierarchical Universe: III. Mock Redshift Surveys
• The UZC-SSRS2 Group Catalog
• Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
• Galaxy Groups at Intermediate Redshift
• Three-Dimensional Identification and Reconstruction of Galaxy Systems within Deep Redshift Surveys
• The Dynamics of Poor Systems of Galaxies
• The Observational Mass Function of Loose Galaxy Groups
• The redshift-space two-point correlation functions of galaxies and groups in the Nearby Optical Galaxy sample
• Morphology and luminosity segregation of galaxies in nearby loose groups
• Are the nearby groups of galaxies gravitationally bound objects?
• Clustering of loose groups and galaxies from the Perseus--Pisces Survey
• Redshift Evolution of the Nonlinear Two-Point Correlation Function
• Clusters and Groups of Galaxies in the Simulated Local Universe
• Ab Initio Formation of Galaxies, Groups and Large-Scale Structure