Open AccessCross‐correlations of X‐ray and optically selected clusters with near‐infrared and optical galaxies
Author(s) -
Sánchez Ariel G.,
Lambas Diego G.,
Böhringer Hans,
Schuecker Peter
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09377.x
Subject(s) - physics , astrophysics , galaxy cluster , rosat , field galaxy , brightest cluster galaxy , luminosity , galaxy group , virial mass , galaxy , virial theorem , astronomy , cluster (spacecraft) , luminosity function , redshift , redshift survey , computer science , programming language
We compute the real‐space cluster–galaxy cross‐correlation ξ cg ( r ) using the ROSAT ‐ESO Flux Limited X‐ray (REFLEX) cluster survey, a group catalogue (2dFGGC) constructed from the final version of the Two‐degree Field Galaxy Redshift Survey (2dFGRS), and galaxies extracted from the Two Micron All Sky Survey (2MASS) and Automated Plate Measurement (APM) surveys. This first detailed calculation of the cross‐correlation for X‐ray clusters and groups is consistent with previous works and shows that ξ cg ( r ) cannot be described by a single power law. We analyse the clustering dependence on the cluster X‐ray luminosity L X and virial mass M vir thresholds as well as on the galaxy limiting magnitude. We also make a comparison of our results with those obtained for the halo–mass cross‐correlation function in a ΛCDM N ‐body simulation to infer the scale dependence of galaxy bias around clusters. Our results indicate that the distribution of galaxies shows a significant anti‐bias at highly non‐linear small cluster‐centric distances, b cg ( r ) ≃ 0.7 , irrespective of the group/cluster virial mass or X‐ray luminosity and galaxy characteristics. This shows that a generic process controls the efficiency of galaxy formation and evolution in high‐density regions. On larger scales, b cg ( r ) rises to a nearly constant value of the order of unity, the transition occurring at approximately 2 h −1 Mpc for 2dF groups and 5 h −1 Mpc for REFLEX clusters.