Dynamics of Abell 3266 - I. An Optical View of a Complex Merging Cluster

Abstract

We present spectroscopy of 880 galaxies within a 2-degree field around the massive, merging cluster Abell 3266. This sample, which includes 704 new measurements, was combined with the existing redshifts measurements to generate a sample of over 1300 spectroscopic redshifts; the largest spectroscopic sample in the vicinity of A3266 to date. We define a cluster sub-sample of 790 redshifts which lie within a velocity range of 14,000 to 22,000 kms${}^{-1}$ and within 1 degree of the cluster centre. A detailed structural analysis finds A3266 to have a complex dynamical structure containing six groups and filaments to the north of the cluster as well as a cluster core which can be decomposed into two components split along a northeast-southwest axis, consistent with previous X-ray observations. The mean redshift of the cluster core is found to be $0.0594\pm 0.0005$ and the core velocity dispersion is given as $1462_{-99}^{+99}$ kms${}^{-1}$. The overall velocity dispersion and redshift of the entire cluster and related structures are $1337_{-67}^{+67}$ kms${}^{-1}$ and $0.0596\pm 0.0002$, respectively, though the high velocity dispersion does not represent virialised motions but rather is due to relative motions of the cluster components. We posit A3266 is seen following a merger along the northeast southwest axis, however, the rich substructure in the rest of the cluster suggests that the dynamical history is more complex than just a simple merger with a range of continuous dynamical interactions taking place. It is thus likely that turbulence in A3266 is very high, even for a merging cluster.

11 pages, 9 figures, 3 tables, accepted for publication in MNRAS

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• KAT-7 observations of a mass-selected sample of galaxy clusters
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Cited by in corpus (9)

• The MeerKAT Galaxy Cluster Legacy Survey I. Survey Overview and Highlights
• Studying the merging cluster Abell 3266 with eROSITA
• Radio fossils, relics, and haloes in Abell 3266: cluster archaeology with ASKAP-EMU and the ATCA
• The merging galaxy cluster Abell 3266 at low radio frequencies
• Mass-Velocity Dispersion Relation in HIFLUGCS Galaxy Clusters
• Measuring the ICM velocity structure within the A3266 galaxy cluster
• A Lack of Evidence for Global Ram-pressure Induced Star Formation in the Merging Cluster Abell 3266
• Intracluster Medium Fluctuations on Scales up to 1 Mpc: A Combined eROSITA and SPT/Planck Analysis of Abell 3266
• Chemical enrichment of ICM within the A3266 cluster I: radial profiles