REVEALING THE GALAXY ASSOCIATIONS IN ABELL-119

We report the results of an analysis of the hierarchical properties of the cluster of galaxies Abell II9. Observational data from the ESO Ne arby Abell Cluster Survey (ENACS) are used, complemented by data from previous studies, while the analysis is performed with the S-tree meth od. The main physical system and three subgroups with truncated Gaussi an velocity distributions are identified; we call these subgroups 'gal axy associations'. The mass centre of the core of the main system is s hown to coincide with the X-ray centre of the cluster. An alignment of the mass centres of the three galaxy associations is also shown.