Bibcode
Boschin, W.; Girardi, M.; Barrena, R.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 434, Issue 1, p.772-783
Fecha de publicación:
9
2013
Número de citas
23
Número de citas referidas
20
Descripción
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
˜ 0.2693 and the global line-of-sight velocity
dispersion σV ˜ 1000 km s-1.
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
Msys ˜ 1-3 × 10^{15}h_{70}^{-1}M_{⊙} 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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