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Description
We study the dynamical status of the galaxy system ZwCl 2341.1+0000, a filamentary multi-Mpc galaxy structure associated with a complex diffuse radio emission. Our analysis is mainly based on new spectroscopic data for 128 galaxies acquired at the Italian Telescopio Nazionale Galileo. We also use optical data available in the Sloan Digital Sky Survey and X-ray data from the Chandra archive. We select 101 cluster member galaxies and compute the cluster redshift <z>~0.2693 and the global line-of-sight velocity dispersion {sigma}_V_~1000km/s. Our optical analysis agrees with the presence of at least three, likely four or more, optical subclusters causing the south-south-east-north-north-west (SSE-NNW) elongation of the galaxy distribution and a significant velocity gradient in the south-north direction. In particular, we detect an important low-velocity subclump in the southern region, roughly coincident with the brightest peak of the diffuse radio emission but with a clear offset between the optical and radio peaks. We also detect one (or two) optical subcluster(s) at north, in correspondence with the second brightest radio emission, and another one in the central cluster region, where a third diffuse radio source has been recently detected. A more refined analysis involving the study of the 2D galaxy distribution suggests an even more complex structure. Depending on the adopted model, we obtain a mass estimate M_sys_~1-3x10^15^h_70_^-1^M_{sun} for the whole system. As for the X-ray analysis, we confirm the SSE-NNW elongation of the intracluster medium and detect four significant peaks. The X-ray emission is strongly asymmetric and offsetted with respect to the galaxy distribution, thus suggesting a merger caught in the phase of post-core-core passage. Our findings support two possible hypotheses for the nature of the diffuse radio emission of ZwCl 2341.1+0000: a two relics + halo scenario or diffuse emission associated with the infall and merging of several galaxy groups during the first phase of the cluster formation.
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