Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/49798

Title

Abell 1201: the anatomy of a cold front cluster from combined optical and x-ray data

Author(s)

Owers, Matthew S.;  Nulsen, Paul E. J.;  Couch, Warrick J.;  Markevitch, Maxim L.;  Poole, Gregory B.

Abstract

We present a combined X-ray and optical analysis of the cold front cluster Abell 1201 using archival Chandra data and multi-object spectroscopy taken with the 3.9 m Anglo-Australian and 6.5 m Multiple Mirror Telescopes. This paper represents the first in a series presenting a study of a sample of cold front clusters selected from the Chandra archives with the aim of relating cold fronts to merger activity, understanding the dynamics of mergers and their effect on the cluster constituents. The Chandra X-ray imagery of Abell 1201 reveals two conspicuous surface brightness discontinuities that are shown to be cold fronts, and a remnant core structure. Temperature maps reveal a complex multiphase temperature structure with regions of hot gas interspersed with fingers of cold gas. Our optical analysis is based on a sample of 321 confirmed members, whose mean redshift is z = 0.1673 ± 0.0002 and velocity dispersion is 778 ± 36 km s–1. We search for dynamical substructure and find clear evidence for multiple localized velocity substructures coincident with overdensities in the galaxy surface density. Most notably, we find the structure coincident with the remnant X-ray core. Despite the clear evidence for dynamical activity, we find the peculiar velocity distribution does not deviate significantly from Gaussian. We apply two-body dynamical analyses in order to assess which of the substructures are bound, and thus dynamically important in terms of the cluster merger history. We propose that the cold fronts in Abell 1201 are a consequence of its merger with a smaller subunit, which has induced gas motions that gave rise to "sloshing" cold fronts. Abell 1201 illustrates the value of combining multiwavelength data and multiple substructure detection techniques when attempting to ascertain the dynamical state of a cluster.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Astrophysical Journal, Vol. 692, no. 1 (Feb 2009), pp. 702-722

Publication year

2009

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

Abell 1201;  Chandra observation;  Cluster galaxies;  Core;  Dynamics;  Fiber-fed;  Galaxy Redshift Survey;  Individual galaxies;  Multiwavelength analysis;  Perseus cluster;  Rich clusters;  Spectrograph;  Velocity dispersions;  XMM-Newton observations;  X-rays

Publisher

Institute of Physics Publishing

ISSN

0004-637X

Publisher URL

http://dx.doi.org/10.1088/0004-637x/692/1/702

Copyright

Copyright © 2009 The American Astronomical Society. All rights reserved. The American Astronomical Society does not allow institutions to archive either the accepted manuscript or the published version of the article. However, you can find an earlier version of the full text here: http://arxiv.org/abs/0810.4650.

Peer reviewed