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تسجيل مستخدم جديدLoCuSS: Testing hydrostatic equilibrium in galaxy clusters
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We test the assumption of hydrostatic equilibrium in an X-ray luminosity selected sample of 50 galaxy clusters at $0.15<z<0.3$ from the Local Cluster Substructure Survey (LoCuSS). Our weak-lensing measurements of $M_{500}$ control systematic biases to sub-4 per cent, and our hydrostatic measurements of the same achieve excellent agreement between XMM-Newton and Chandra. The mean ratio of X-ray to lensing mass for these 50 clusters is $beta_{rm X}=0.95pm0.05$, and for the 44 clusters also detected by Planck, the mean ratio of Planck mass estimate to LoCuSS lensing mass is $beta_{rm P}=0.95pm0.04$. Based on a careful like-for-like analysis, we find that LoCuSS, the Canadian Cluster Comparison Project (CCCP), and Weighing the Giants (WtG) agree on $beta_{rm P}simeq0.9-0.95$ at $0.15<z<0.3$. This small level of hydrostatic bias disagrees at $sim5sigma$ with the level required to reconcile Planck cosmology results from the cosmic microwave background and galaxy cluster counts.
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