Structure and Dynamics of Abell 2634

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Session 53 -- Clusters of Galaxies I
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

[53.06] Structure and Dynamics of Abell 2634

J.M. Solanes, M. Scodeggio, R. Giovanelli, M.P. Haynes (Cornell U./NAIC)

Two samples, ---one containing 200 galaxies within two degrees from the cluster center and a second, magnitude-limited, of 118 galaxies within the central half degree---, are used to examine the structure and dynamics of A2634. We find that the properties of the early-type galaxy component agree with those expected for a relaxed system, while the late-type population is virtually absent from the central parts of the cluster and displays a multimodal velocity distribution.

Several statistical tests of substructure are used to investigate possible signatures of a recent collision of this cluster with a large subunit, a scenario suggested by X-ray and radio observations of the central cluster region. The absence of significant clumpiness in the galaxy component of A2634 does not support the ocurrence of a merger of two comparable subunits moving in the plane of the sky. We cannot exclude, however, the existence of small loose groups of spirals infalling towards the cluster center along the line-of-sight.

We also investigate the dynamics of the system formed by A2634 ($cz_{hel}=9240\,\rm km\,s^{-1}$) and three poorer galaxy concentrations: A2666 ($cz_{hel}=8134\,\rm km\,s^{-1}$), and two spiral rich groups at $cz_{hel} \sim7500\,\rm km\,s^{-1}$ and $\sim11{,}500\,\rm km\,s^{-1}$, which are located to the east of A2634 center at median distances of $2\fdg8$, $1\fdg1$ and $0\fdg 6$, respectively. Simple energetic considerations suggest that this four-body system is gravitationally unbound, despite the proximity among its members.

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