Clustering due to cluster galaxies

This paper presents a calculation of the contribution that galaxies in clusters make towards the clustering exhibited by all galaxies. It is shown that, within observational uncertainties, cluster galaxies may be responsible for all the clustering measured by the galaxy-galaxy correlation function, ξgg (r). This extends Peeble's result that cluster galaxies make a significant contribution to the two-point function. This then accounts for the apparent paradox that the two-point correlation function in redshift space is elongated along the line-of-sight on scales where ξgg(r) is significantly less than unity. It has previously been argued that the elongation is a direct indication of non-linear dynamical effects. (Author)