Mass-concentration relation of clusters of galaxies from CFHTLenS

TL;DR

This study uses weak lensing data from CFHTLenS to measure the mass-concentration relation of about 200 galaxy clusters individually, accounting for various observational effects, and finds results consistent with simulations but with slight deviations.

Contribution

It presents a method to derive the mass-concentration relation from individual cluster profiles, avoiding stacking, and demonstrates its reliability through simulations.

Findings

The derived $M$-$c$ relation agrees with simulation predictions.

Monte Carlo simulations show the method's robustness despite low signal-to-noise.

A slight deviation from Planck cosmology predictions was observed.

Abstract

Based on weak lensing data from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), in this paper we study the mass-concentration ($M$-$c$) relation for $\sim 200$ redMaPPer clusters in the fields. We extract the $M$-$c$ relation by measuring the density profiles of individual clusters instead of using stacked weak lensing signals. By performing Monte Carlo simulations, we demonstrate that although the signal-to-noise ratio for each individual cluster is low, the unbiased $M$-$c$ relation can still be reliably derived from a large sample of clusters by carefully taking into account the impacts of shape noise, cluster center offset, dilution effect from member or foreground galaxies, and the projection effect. Our results show that within error bars the derived $M$-$c$ relation for redMaPPer clusters is in agreement with simulation predictions. There is a weak deviation in that the halo concentrations calibrated by Monte Carlo simulations are somewhat higher than that predicted from ${\it Planck}$ cosmology.