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

Galaxy clusters are biased tracers of the underlying matter density field. At very large radii beyond about 10 Mpc h(-1), 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 catalogue, 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 cold dark matter standard cosmological model show an agreement within 2 sigma. The mean measurements of bias and mass over the full catalogue give M-200(c) = (4.9 +/- 0.3) x 10(13) M-circle dot/h and b(h)sigma(2)(8) = 1.2 +/- 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 +/- 0.10.