Red Sequence Cluster Finding in the Millennium Simulation

Abstract

We investigate halo mass selection properties of red-sequence cluster finders using galaxy populations of the Millennium Simulation (MS). A clear red sequence exists for MS galaxies in massive halos at redshifts z < 1, and we use this knowledge to inform a cluster-finding algorithm applied to 500 Mpc/h projections of the simulated volume. At low redshift (z=0.4), we find that 90% of the clusters found have galaxy membership dominated by a single, real-space halo, and that 10% are blended systems for which no single halo contributes a majority of a cluster's membership. At z=1, the fraction of blends increases to 22%, as weaker redshift evolution in observed color extends the comoving length probed by a fixed range of color. Other factors contributing to the increased blending at high-z include broadening of the red sequence and confusion from a larger number of intermediate mass halos hosting bright red galaxies of magnitude similar to those in higher mass halos. Our method produces catalogs of cluster candidates whose halo mass selection function, p(M|\Ngal,z), is characterized by a bimodal log-normal model with a dominant component that reproduces well the real-space distribution, and a redshift-dependent tail that is broader and displaced by a factor ~2 lower in mass. We discuss implications for X-ray properties of optically selected clusters and offer ideas for improving both mock catalogs and cluster-finding in future surveys.

final version to appear in MNRAS. Appendix added on purity and completeness, small shift in red sequence due to correcting an error in finding it

References in corpus (9)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• The high redshift galaxy population in hierarchical galaxy formation models
• The luminosities, sizes and velocity dispersions of Brightest Cluster Galaxies: Implications for formation history
• The build-up of the colour-magnitude relation in galaxy clusters since z~0.8
• The X-Ray Luminosity--Mass Relation for Local Clusters of Galaxies
• Cosmological Constraints from the Red-Sequence Cluster Survey
• Weak Lensing by Galaxies in Groups and Clusters: I.--Theoretical Expectations
• ChaMP Serendipitous Galaxy Cluster Survey
• Spectroscopy of moderately high-redshift RCS-1 clusters

Cited by in corpus (6)

• The Red-Sequence Luminosity Function in Galaxy Clusters since z~1
• The Complex Structure of the Cl 1604 Supercluster at z~0.9
• Chandra X-ray Observations of the 0.6 < z < 1.1 Red-Sequence Cluster Survey Sample
• Cross-Calibration of Cluster Mass-Observables
• Issues in joint SZ and optical cluster finding
• Evidence for line-of-sight structure in a comparison of X-ray and optical observations of the high-redshift cluster RCS043938-2904.7