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.
Categories: astro-ph.CO