Weak-lensing-inferred scaling relations of galaxy clusters in the RCS2: mass-richness, mass-concentration, mass-bias, and more

¹ Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany
e-mail: vuitert@ucl.ac.uk
² Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
³ University College London, Gower Street, London WC1E 6BT, UK
⁴ South African Astronomical Observatory, PO Box 9, 7935 Observatory, South Africa
⁵ The Department of Astronomy and Astrophysics, and the Kavli Institute for Cosmological Physics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
⁶ Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario, M5S 3H4, Canada

Received: 11 June 2015
Accepted: 12 October 2015

Abstract

We study a sample of ~10⁴ galaxy clusters in the redshift range 0.2 <z< 0.8 with masses M₂₀₀ > 5×10¹³ h₇₀^-1 M_⊙, discovered in the second Red-sequence Cluster Survey (RCS2). The depth and excellent image quality of the RCS2 enabled us to detect the cluster-mass cross-correlation up to z ~ 0.7. To obtain cluster masses, concentrations, and halo biases, we fit a cluster halo model simultaneously to the lensing signal and to the projected density profile of red-sequence cluster members, because the latter provides tight constraints on the cluster miscentring distribution. We parametrised the mass-richness relation as M₂₀₀ = A × (N₂₀₀/ 20)^α and find A =(15.0±0.8)×10¹³ h₇₀^-1 M_⊙ and α = 0.73 ± 0.07 at low redshift (0.2 < z < 0.35). At intermediate redshift (0.35 < z < 0.55), we find a higher normalisation, which points towards a fractional increase in the richness towards lower redshift caused by the build-up of the red sequence. The miscentring distribution is well constrained. Only ~30% of our BCGs coincide with the peak of the dark matter distribution. The distribution of the remaining BCGs are modelled with a 2D-Gaussian, whose width increases from 0.2 to 0.4 h₇₀^-1 Mpc towards higher masses. The ratio of width and r₂₀₀ is constant with mass and has an average value of 0.44 ± 0.01. The mass-concentration and mass-bias relations agree fairly well with literature results at low redshift, but have a higher normalisation at higher redshifts, possibly because of selection and projection effects. The concentration of the satellite distribution decreases with mass and is correlated to the concentration of the halo.