Multiple merging in the Abell cluster 1367 ^*,**

¹ Universitá degli Studi di Milano-Bicocca, P.zza della Scienza 3, 20126 Milano, Italy e-mail: [Luca.Cortese;Giuseppe.Gavazzi]@mib.infn.it
² Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille, France e-mail: [alessandro.boselli;jorge.iglesias]@oamp.fr
³ Instituto Nactional de Astrofisica, Optica y Electronica, Apartado Postal 51, CP 72000 Puebla, Pue., Mexico e-mail: carrasco@transum.inaoep.mx
⁴ Observatorio Astronomico Nacional/UNAM, Ensenada BC, Mexico

Received: 3 March 2004
Accepted: 4 June 2004

Abstract

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 and a scale . The cluster appears elongated from the North-West to the South-East with two main density peaks associated with two substructures. The North-West subcluster is probably in the early phase of merging into the South-East 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 South-East 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.