Description
A detailed dynamical analysis of the nearby rich Norma cluster (ACO 3627) is presented. From radial velocities of 296 cluster members, we find a mean velocity of 4871+/-54km/s and a velocity dispersion of 925km/s. The mean velocity of the E/S0 population (4979+/-85km/s) is offset with respect to that of the S/Irr population (4812+/-70km/s) by {Delta}v=164km/s in the cluster rest frame. This offset increases towards the core of the cluster. The E/S0 population is free of any detectable substructure and appears relaxed. Its shape is clearly elongated with a position angle that is aligned along the dominant large-scale structures in this region, the so-called Norma wall. The central cD galaxy has a very large peculiar velocity of 561km/s which is most probably related to an ongoing merger at the core of the cluster.
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