Luminous Red Galaxy Population in Clusters at $0.2\le z\le 0.6$

Abstract

We investigate statistical properties of LRGs in a sample of X-ray selected galaxy clusters at intermediate redshift ($0.2\le z\le 0.6$). The LRGs are selected based on carefully designed color criteria, and the cluster membership is assessed via photometric redshifts. As clusters and LRGs are both viewed as promising tracer of the underlying dark matter distribution, understanding the distribution of LRGs within clusters is an important issue. Our main findings include: 1. The halo occupation distribution of LRGs inside our cluster sample is $N(M)=k\times (M/10^{14}{)}^a$ where $a=0.620\pm 0.105$ and $k=1.425\pm 0.285$ assuming a Poisson distribution for $N(M)$. 2. The halo occupation distribution of LRGs ($N(M)$) and the satellite distribution of LRGs ($N-1(M)$) are both consistent with being Poisson. To be more quantitative, we find $Var(N)/<N>=1.428\pm 0.351$ and $Var(N-1)/<N-1>=1.823\pm 0.496$ 3. The radial profile of LRGs within clusters when fitted with a NFW profile gives a concentration of $17.5_{-4.3}^{+7.1}$ ($6.0_{-1.9}^{+3.2}$) including (excluding) BLRGs (Brightest LRGs). We also discuss the implications of these observations on the evolution of massive galaxies in clusters.

13 pages, 13 figures, 2 tables

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Cited by in corpus (5)

• An Optical Catalog of Galaxy Clusters Obtained from an Adaptive Matched Filter Finder Applied to SDSS DR6
• The 2dF-SDSS LRG and QSO survey: evolution of the clustering of luminous red galaxies since z = 0.6
• Luminous Red Galaxy Halo Density Field Reconstruction and Application to Large Scale Structure Measurements
• Passive Evolution of Galaxy Clustering
• Inferring Host Dark Matter Halo Masses of Individual Galaxies from Neighboring Galaxy Counts