Dynamical state of galaxy clusters evaluated from X-ray images

Abstract

X-ray images of galaxy clusters often show disturbed structures that are indications of cluster mergers. To complement our previous work on the dynamical state of 964 clusters observed by Chandra, we process the X-ray images for 1308 clusters from XMM-Newton archival data, together with the images of 22 clusters newly released by Chandra, and we evaluate their dynamical state from these X-ray images. The concentration index c, the centroid shift ω and the power ratio P₃/P₀ are calculated in circular regions with a certain radius of 500 kpc, and the morphology index δ is estimated within elliptical regions that can be adapted to the cluster size and shape. In addition, the dynamical parameters for 42 clusters previously estimated from Chandra images are upgraded based on the newly available redshifts. Good consistence is found between dynamical parameters derived from XMM-Newton and Chandra images for the overlapped sample of clusters in the two data sets. The dependence of mass scaling relations on the dynamical state is shown by using the data of 388 clusters. All data and related software are available at http://zmtt.bao.ac.cn/galaxy_clusters/dyXimages/.