AMICO galaxy clusters in KiDS-DR3: Measurement of the halo bias and power spectrum normalization from a stacked weak lensing analysis

TL;DR

This study measures the halo bias-mass relation using weak lensing of galaxy clusters from KiDS-DR3, finding results consistent with standard cosmological models and constraining the power spectrum normalization.

Contribution

It provides the first observational measurement of the halo bias-mass relation for a large cluster sample in KiDS-DR3, and constrains a_8 using weak lensing data.

Findings

Halo bias and mass measurements are consistent with aCDM predictions within 2a.

Mean cluster mass is approximately 4.9 7 M_70/h.

Power spectrum normalization a_8 is constrained to 0.63 b1 0.10.

Abstract

Galaxy clusters are biased tracers of the underlying matter density field. At very large radii beyond about 10 Mpc/\textit{h}, the shear profile shows evidence of a second-halo term. This is related to the correlated matter distribution around galaxy clusters and proportional to the so-called halo bias. We present an observational analysis of the halo bias-mass relation based on the AMICO galaxy cluster catalog, comprising around 7000 candidates detected in the third release of the KiDS survey. We split the cluster sample into 14 redshift-richness bins and derive the halo bias and the virial mass in each bin by means of a stacked weak lensing analysis. The observed halo bias-mass relation and the theoretical predictions based on the $\Lambda$CDM standard cosmological model show an agreement within $2\sigma$. The mean measurements of bias and mass over the full catalog give $M_{200c} = (4.9 \pm 0.3) \times 10^{13} M_{\odot}/\textit{h}$ and $b_h \sigma_8^2 = 1.2 \pm 0.1$. With the additional prior of a bias-mass relation from numerical simulations, we constrain the normalization of the power spectrum with a fixed matter density $\Omega_m = 0.3$, finding $\sigma_8 = 0.63 \pm 0.10$.