Photometric properties of Low-Redshift galaxy clusters

A comprehensive multicolor survey was undertaken to investigate global optical properties of Abell clusters of galaxies. This survey was christened the Low-Redshift Cluster Optical Survey (LOCOS). LOCOS was devised to. search for patterns of galaxy evolution induced by the environment. The generated data base contains accurate deep CCD photometric measurements. (Kron-Cousins R, B and I) for a sample of 46 low-redshift (0.04 less than or equal to z less than or equal to 0.18) Abell clusters. This is one of the few large surveys that included the contribution due to dwarf galaxies (about 5.5 mag deeper than the R characteristic magnitude (M-R(*)); Ho = 50 h(50) km s(-1) Mpc(-1), qo = 0). Due to space restrictions only the main results concerning the variations at the bright-end of the luminosity function (LF) are presented here. Other results are presented elsewhere (Lopez-Cruz & Yee 2000a,b). We have detected clear variations at both the bright end and the faint end of the LF. The nature-of the variations at the bright end revealed that poor cD cluster have. dimmer M-R(*). We can explain these variations as a result of dynamical friction. On the other hand, non-cD clusters seem to have unaffected LFs. A third class termed as binary clusters seems to, be a transition class that might have resulted from cluster-cluster mergers.