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Durham University

Department of Physics

Staff profile

Publication details for Professor Ian Smail

Bardeau, S., Soucail, G., Kneib, J.-P., Czoske, O., Ebeling, H., Hudelot, P., Smail, I. & Smith, G.P. (2007). A CFH12k lensing survey of X-ray luminous galaxy clusters II weak lensing analysis and global correlations. Astronomy & astrophysics 470(2): 449-466.

Author(s) from Durham

Abstract

Aims:
We present a wide-field multi-color survey of a homogeneous sample of eleven clusters of galaxies for which we measure total masses and mass distributions from weak lensing. This sample, spanning a small range in both X-ray luminosity and redshift, is ideally suited to determining the normalisation of scaling relations between X-ray properties of clusters and their masses (the M-TX and the M-LX relations) and also estimating the scatter in these relations at a fixed luminosity.

Methods:
The eleven clusters in our sample are all X-ray luminous and span a narrow redshift range at z = 0.21 ± 0.04. The weak lensing analysis of the sample is based on ground-based wide-field imaging obtained with the CFH12k camera on CFHT. We use the methodology developed and applied previously on the massive cluster Abell 1689. A Bayesian method, implemented in the Im2shape software, is used to fit the shape parameters of the faint background galaxies and to correct for PSF smearing. A multi-color selection of the background galaxies is applied to retrieve the weak lensing signal, resulting in a background density of sources of ~10 galaxies per square arc minute. With the present data, shear profiles are measured in all clusters out to at least 2 Mpc (more than 15´ from the center) with high confidence. The radial shear profiles are fitted with different parametric mass profiles and the virial mass M200 is estimated for each cluster and then compared to other physical properties.

Results:
Scaling relations between mass and optical luminosity indicate an increase of the M/L ratio with luminosity (M/L ∝ L0.8) and a LX-M200 relation scaling as LX ∝ M2000.83 ± 0.11 while the normalization of the M200 ∝ TX3/2 relation is close to the one expected from hydrodynamical simulations of cluster formation as well as previous X-ray analyses. We suggest that the dispersion in the M200-TX and M200-LX relations reflects the different merging and dynamical histories for clusters of similar X-ray luminosities and intrinsic variations in their measured masses. Improved statistics of clusters over a wider mass range are required for a better control of the intrinsic scatter in scaling relations.