Three southern cD clusters of galaxies Klemola 44, Sersic 40/6 and 2354 - 35

Abstract

We have measured b27 magnitudes in three rich southern clusters with central cD galaxies. The brightest few galaxies in each case show a marked concentration to the centre. All three have (M/L)b between 110 and 220, and their major-axis position angles align with the major axes of the cD's. Klemola 44 and 2354 – 35 are similar in velocity dispersion and total luminosity. They differ in that the cD in Klemola 44 has a bound population whose lifetime against accretion by means of dynamical friction is a small fraction of the cluster lifetime. Ultimately, the captured galaxies will make the cD luminosity roughly the same as that of the relatively isolated central galaxy in 2354 – 35, any bound satellites of which must have been already cannibalized. Sérsic 40/6 is a larger cluster with a higher velocity dispersion and mass, in which the core galaxies do not seem to be bound to the central cD galaxy. In Klemola 44 the cD galaxy core has a significant peculiar velocity with respect to the cluster mean velocity.