AMICO galaxy clusters in KiDS-DR3: cosmological constraints from large-scale stacked weak lensing profiles

TL;DR

This study uses large-scale weak lensing profiles of galaxy clusters from KiDS-DR3 to constrain cosmological parameters, particularly the matter density, supporting the ${ m extLambda CDM}$ model with results consistent with CMB measurements.

Contribution

It presents a comprehensive Bayesian analysis of shear profiles from a large galaxy cluster sample to simultaneously determine cluster masses and cosmological parameters, especially ${ m extOmega}_M$, using scales up to 35 Mpc/h.

Findings

Successful modeling of shear profiles to estimate cluster masses and ${ m extOmega}_M$.

Detection of the 2-halo term in stacked lensing signals.

Constraint on ${ m extOmega}_M = 0.29 \u00b1 0.02$ consistent with CMB results.

Abstract

Context. The large-scale mass distribution around dark matter haloes hosting galaxy clusters provides sensitive cosmological information. Aims. In this work, we make use of a large photometric galaxy cluster sample, constructed from the public Third Data Release of the Kilo-Degree Survey, and the corresponding shear signal, to assess cluster masses and test the concordance ${\Lambda}$-cold dark matter (${\Lambda}$CDM) model. In particular, we study the weak gravitational lensing effects on scales beyond the cluster virial radius, where the signal is dominated by correlated and uncorrelated matter density distributions along the line-of-sight. The analysed catalogue consists of 6962 galaxy clusters, in the redshift range $0.1 \leq z \leq 0.6$ and with signal-to-noise ratio larger than 3.5. Methods. We perform a full Bayesian analysis to model the stacked shear profiles of these clusters. The adopted likelihood function considers both the small-scale 1-halo term, used primarily to constrain the cluster structural properties, and the 2-halo term, that can be used to constrain cosmological parameters. Results. We find that the adopted modelling is successful to assess both the cluster masses and the total matter density parameter, ${\Omega}_M$, when fitting shear profiles up to the largest available scales of 35 Mpc/h. Moreover, our results provide a strong observational evidence of the 2-halo signal in the stacked gravitational lensing of galaxy clusters, further demonstrating the reliability of this probe for cosmological studies. The main result of this work is a robust constraint on ${\Omega}_M$, assuming a flat ${\Lambda}$CDM cosmology. We get ${\Omega}_M = 0.29 \pm 0.02$, estimated from the full posterior probability distribution, consistent with the estimates from cosmic microwave background experiments.