CODEX weak lensing: Concentration of galaxy clusters at z ~ 0.5

Journal article

We present a stacked weak lensing analysis of 27 richness selected galaxy clusters at $0.40 \leqslant z \leqslant 0.62$ in the CODEX survey. The fields were observed in 5 bands with the CFHT. We measure the stacked surface mass density profile with a $14\sigma$ significance in the radial range $0.1 < R\ Mpc\ h^{-1} < 2.5$. The profile is well described by the halo model, with the main halo term following an NFW profile and including the off-centring effect. We select the background sample using a conservative colour-magnitude method to reduce the potential systematic errors and contamination by cluster member galaxies. We perform a Bayesian analysis for the stacked profile and constrain the best-fit NFW parameters $M_{200c} = 6.6^{+1.0}_{-0.8} \times 10^{14} h^{-1} M_{\odot}$ and $c_{200c} = 3.7^{+0.7}_{-0.6}$. The off-centring effect was modelled based on previous observational results found for redMaPPer SDSS clusters. Our constraints on $M_{200c}$ and $c_{200c}$ allow us to investigate the consistency with numerical predictions and select a concentration-mass relation to describe the high richness CODEX sample. Comparing our best-fit values for $M_{200c}$ and $c_{200c}$ with other observational surveys at different redshifts, we find no evidence for evolution in the concentration-mass relation, though it could be mitigated by particular selection functions. Similar to previous studies investigating the X-ray luminosity-mass relation, our data suggests a lower evolution than expected from self-similarity.

Authors: Cibirka, N; Cypriano, E; Brimioulle, F; Gruen, D; Erben, T

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 468
• Issue: 1
• Pages: 1092-1116
• Publication date: 2017-03-01
• Acceptance date: 2017-02-22
• DOI: 10.1093/mnras/stx484
• EISSN: 1365-2966
• ISSN: 0035-8711
• Keywords: galaxy: clusters; gravitational lensing: weak