Multiple merging in the Abell cluster 1367 . ⋆

We present a dynamical analysis of the central ∼ 1.3 square degrees of the cluster of galaxies Abell 1367, based on 273 redshift measurements (of which 119 are news). From the analysis of the 146 confirmed cluster members we derive a significantly non-Gaussian velocity distribution, with a mean location CBI = 6484±81 km s −1 and a scale SBI = 891 ± 58 km s −1. The cluster appears elongated from the NorthWest to the SouthEast with two main density peaks associated with two substructures. The NorthWest subcluster is probably in the early phase of merging into the SouthEast substructure (∼ 0.2 Gyr before core crossing). A dynamical study of the two subclouds points out the existence of a group of star-forming galaxies infalling into the core of the SouthEast subcloud and suggests that two other groups are infalling into the NW and SE subclusters respectively. These three subgroups contain a higher fraction of star-forming galaxies than the cluster core, as expected during merging events. Abell 1367 appears as a young cluster currently forming at the intersection of two filaments.