Scaling relations of the colour-detected cluster RzCS 052 at z=1.016 and of some other high redshift clusters

TL;DR

This paper reports the discovery and analysis of a high-redshift galaxy cluster at z=1.016, examining its properties, scaling relations, and implications for cluster evolution, using multi-wavelength data and novel statistical methods.

Contribution

It introduces a Bayesian approach for measuring cluster properties and provides insights into the evolution of cluster scaling relations at high redshift.

Findings

The cluster follows known L_X-sigma_v relation for high-z clusters.

Halo occupation number suggests a possible break in scaling relations at z~1.

No strong galaxy merging activity detected between z=1 and today.

Abstract

We report on the discovery of the z=1.016 cluster RzCS 052 using a modified red sequence method, followup spectroscopy and X-ray imaging. This cluster has a velocity dispersion of 710+-150 km/s, a virial mass of 4.0e14 Msol (based on 21 spectroscopically confirmed members) and an X-ray luminosity of (0.68+- 0.47)e44 ergs/s in the [1-4] keV band. This optically selected cluster appears to be of richness class 3 and to follow the known L_X-sigma_v relation for high redshift X-ray selected clusters. Using these data, we find that the halo occupation number for this cluster is only marginally consistent with what expected assuming a self-similar evolution of cluster scaling relations, suggesting perhaps a break of them at z~1. We also rule out a strong galaxy merging activity between z=1 and today. Finally, we present a Bayesian approach to measuring cluster velocity dispersions and X-ray luminosities in the presence of a background: we critically reanalyze recent claims for X-ray underluminous clusters using these techniques and find that the clusters can be accommodated within the existing L_X -sigma_v relation.