Mass bias and cosmological constraints from Planck cluster clustering

Abstract

Aims. We analysed the 3D clustering of the Planck sample of Sunyaev–Zeldovich (SZ) selected galaxy clusters, focusing on the redshift-space two-point correlation function (2PCF). We compared our measurements to theoretical predictions of the standard Λ cold dark matter (ΛCDM) cosmological model, deriving an estimate of the Planck mass bias, bSZ, and cosmological parameters. Methods. We measured the 2PCF of the sample in the cluster-centric radial range r ∈ [10, 150] h−1 Mpc, considering 920 galaxy clusters with redshift z ≤ 0.8. A Markov chain Monte Carlo analysis was performed to constrain bSZ, assuming priors on cosmological parameters from Planck cosmic microwave background (CMB) results. We also adopted priors on bSZ from external data sets to constrain the cosmological parameters Ωm and σ8. Results. We obtained (1−bSZ) = 0.62−0.11+0.14, which agrees with the value required to reconcile primary CMB and cluster count observations. By adopting priors on (1 − bSZ) from external data sets, we derived results on Ωm that fully agree and are competitive, in terms of uncertainties, with those derived from cluster counts. This confirms the importance of including clustering in cosmological studies in order to fully exploit the information from galaxy cluster statistics. On the other hand, we found that σ8 is not constrained.