Testing for X-Ray–SZ Differences and Redshift Evolution in the X-Ray Morphology of Galaxy Clusters
Author(s)Nurgaliev, D.; Benson, B. A.; Bleem, L.; Bocquet, S.; Forman, W. R.; Garmire, G. P.; Gupta, N.; Hlavacek-Larrondo, J.; Mohr, J. J.; Nagai, D.; Rapetti, D.; Stark, A. A.; Stubbs, C. W.; Vikhlinin, A.; McDonald, Michael A.; ... Show more Show less
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We present a quantitative study of the X-ray morphology of galaxy clusters, as a function of their detection method and redshift. We analyze two separate samples of galaxy clusters: a sample of 36 clusters at 0.35 < z < 0.9 selected in the X-ray with the ROSAT PSPC 400 deg 2 survey, and a sample of 90 clusters at 0.25 < z < 1.2 selected via the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope. Clusters from both samples have similar-quality Chandra observations, which allow us to quantify their X-ray morphologies via two distinct methods: centroid shifts (w) and photon asymmetry (A phot ). The latter technique provides nearly unbiased morphology estimates for clusters spanning a broad range of redshift and data quality. We further compare the X-ray morphologies of X-ray- and SZ-selected clusters with those of simulated clusters. We do not find a statistically significant difference in the measured X-ray morphology of X-ray and SZ-selected clusters over the redshift range probed by these samples, suggesting that the two are probing similar populations of clusters. We find that the X-ray morphologies of simulated clusters are statistically indistinguishable from those of X-ray- or SZ-selected clusters, implying that the most important physics for dictating the large-scale gas morphology (outside of the core) is well-approximated in these simulations. Finally, we find no statistically significant redshift evolution in the X-ray morphology (both for observed and simulated clusters), over the range of z ∼ 0.3 to z ∼ 1, seemingly in contradiction with the redshift-dependent halo merger rate predicted by simulations.
DepartmentMIT Kavli Institute for Astrophysics and Space Research
Nurgaliev, D. et al. “Testing for X-Ray–SZ Differences and Redshift Evolution in the X-Ray Morphology of Galaxy Clusters.” The Astrophysical Journal 841, 1 (May 2017): 5. © 2017 The American Astronomical Society. All rights reserved.
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