LoCuSS: The Sunyaev-Zel'dovich Effect and Weak-lensing Mass Scaling Relation
Abstract
We present the first weak-lensing-based scaling relation between galaxy cluster mass, M WL, and integrated Compton parameter Y sph. Observations of 18 galaxy clusters at z ~= 0.2 were obtained with the Subaru 8.2 m telescope and the Sunyaev-Zel'dovich Array. The M WL-Y sph scaling relations, measured at Δ = 500, 1000, and 2500 ρ c , are consistent in slope and normalization with previous results derived under the assumption of hydrostatic equilibrium (HSE). We find an intrinsic scatter in M WL at fixed Y sph of 20%, larger than both previous measurements of M HSE-Y sph scatter as well as the scatter in true mass at fixed Y sph found in simulations. Moreover, the scatter in our lensing-based scaling relations is morphology dependent, with 30%-40% larger M WL for undisturbed compared to disturbed clusters at the same Y sph at r 500. Further examination suggests that the segregation may be explained by the inability of our spherical lens models to faithfully describe the three-dimensional structure of the clusters, in particular, the structure along the line of sight. We find that the ellipticity of the brightest cluster galaxy, a proxy for halo orientation, correlates well with the offset in mass from the mean scaling relation, which supports this picture. This provides empirical evidence that line-of-sight projection effects are an important systematic uncertainty in lensing-based scaling relations.
- Publication:
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The Astrophysical Journal
- Pub Date:
- August 2012
- DOI:
- 10.1088/0004-637X/754/2/119
- arXiv:
- arXiv:1107.5115
- Bibcode:
- 2012ApJ...754..119M
- Keywords:
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- cosmology: observations;
- galaxies: clusters: intracluster medium;
- gravitational lensing: weak;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted version