The Evolution of Structure in X-ray Clusters of Galaxies

Using Chandra archival data, we quantify the evolution of cluster morphology with redshift. Clusters form and grow through mergers with other clusters and groups, and the amount of substructure in clusters in the present epoch and how quickly it evolves with redshift depend on the underlying cosmolo...

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Bibliographic Details
Main Authors: Jeltema, Tesla E. (Contributor), Canizares, Claude R. (Contributor), Buote, David A. (Author), Bautz, Marshall W. (Author)
Other Authors: MIT Kavli Institute for Astrophysics and Space Research (Contributor), Bautz, Mark W. (Contributor)
Format: Article
Language:English
Published: IOP Publishing, 2012-07-31T17:34:37Z.
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Online Access:Get fulltext
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100 1 0 |a Jeltema, Tesla E.  |e author 
100 1 0 |a MIT Kavli Institute for Astrophysics and Space Research  |e contributor 
100 1 0 |a Canizares, Claude R.  |e contributor 
100 1 0 |a Jeltema, Tesla E.  |e contributor 
100 1 0 |a Canizares, Claude R.  |e contributor 
100 1 0 |a Bautz, Mark W.  |e contributor 
700 1 0 |a Canizares, Claude R.  |e author 
700 1 0 |a Buote, David A.  |e author 
700 1 0 |a Bautz, Marshall W.  |e author 
245 0 0 |a The Evolution of Structure in X-ray Clusters of Galaxies 
260 |b IOP Publishing,   |c 2012-07-31T17:34:37Z. 
856 |z Get fulltext  |u http://hdl.handle.net/1721.1/71917 
520 |a Using Chandra archival data, we quantify the evolution of cluster morphology with redshift. Clusters form and grow through mergers with other clusters and groups, and the amount of substructure in clusters in the present epoch and how quickly it evolves with redshift depend on the underlying cosmology. Our sample includes 40 X-ray-selected, luminous clusters from the Chandra archive, and we quantify cluster morphology using the power ratio method of Buote & Tsai. The power ratios are constructed from the moments of the X-ray surface brightness and are related to a cluster's dynamical state. We find that, as expected qualitatively from hierarchical models of structure formation, high-redshift clusters have more substructure and are dynamically more active than low-redshift clusters. Specifically, the clusters with z > 0.5 have significantly higher average third- and fourth-order power ratios than the lower redshift clusters. Of the power ratios, P[subscript 3]/P[subscript 0] is the most unambiguous indicator of an asymmetric cluster structure, and the difference in P[subscript 3]/P[subscript 0] between the two samples remains significant even when the effects of noise and other systematics are considered. After correcting for noise, we apply a linear fit to P[subscript 3]/P[subscript 0] versus redshift and find that the slope is greater than zero at better than 99% confidence. This observation of structure evolution indicates that dynamical state may be an important systematic effect in cluster studies seeking to constrain cosmology, and when calibrated against numerical simulations, structure evolution will itself provide interesting bounds on cosmological models. 
520 |a United States. National Aeronautics and Space Administration. (Contract Number NAS8-01129) 
546 |a en_US 
655 7 |a Article 
773 |t Astrophysical Journal