Luminous Red Galaxies in Clusters: Central Occupation, Spatial Distributions, and Mis-centering

Understand

Luminous Red Galaxies (LRG) from the Sloan Digital Sky Survey are considered among the best understood samples of galaxies, and they are employed in a broad range of cosmological studies.

• Because they form a relatively homogeneous population, with high stellar masses and red colors, they are expected to occupy halos in a relatively simple way.
• In this paper, we study how LRGs occupy massive halos via direct counts in clusters and we reveal several unexpected trends suggesting that the connection between LRGs and dark matter halos may not be straightforward.
• Using the redMaPPer cluster catalog, we derive the central occupation of LRGs as a function richness, Ncen({\lambda}).