LoCuSS: Testing hydrostatic equilibrium in galaxy clusters

Smith, G.P.; Mazzotta, P.; Okabe, N.; Ziparo, F.; Mulroy, S.L.; Babul, A.; Finoguenov, A.; McCarthy, I.G.; Lieu, M.; Bahé, Y.M.; Bourdin, H.; Evrard, A.E.; Futamase, T.; Haines, C.P.; Jauzac, M.; Marrone, D.P.; Martino, R.; May, P.E.; Taylor, J.E.; Umetsu, K.

Abstract

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 M500 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 βX=0.95±0.05βX=0.95±0.05, and for the 44 clusters also detected by Planck, the mean ratio of Planck mass estimate to LoCuSS lensing mass is βP=0.95±0.04βP=0.95±0.04. Based on a careful like-for-like analysis, we find that LoCuSS, the Canadian Cluster Comparison Project, and Weighing the Giants agree on βP≃0.9−0.95βP≃0.9−0.95 at 0.15 < z < 0.3. This small level of hydrostatic bias disagrees at ∼5σ with the level required to reconcile Planck cosmology results from the cosmic microwave background and galaxy cluster counts.

Citation

Smith, G., Mazzotta, P., Okabe, N., Ziparo, F., Mulroy, S., Babul, A., …Umetsu, K. (2016). LoCuSS: Testing hydrostatic equilibrium in galaxy clusters. Monthly Notices of the Royal Astronomical Society: Letters, 456(1), L74-L78. https://doi.org/10.1093/mnrasl/slv175

• Journal Article Type: Article
• Acceptance Date: Nov 4, 2015
• Online Publication Date: Dec 2, 2015
• Publication Date: Feb 11, 2016
• Deposit Date: Feb 10, 2016
• Publicly Available Date: Feb 11, 2016
• Journal: Monthly Notices of the Royal Astronomical Society: Letters
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 456
• Issue: 1
• Pages: L74-L78
• DOI: https://doi.org/10.1093/mnrasl/slv175
• Keywords: Gravitational lensing: weak, Galaxies: clusters: general, Cosmology: observations.
• Public URL: https://durham-repository.worktribe.com/output/1388791