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arXiv · 0710.1023

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

S. Andreon·R. De Propris·E. Puddu·L. Giordano·H. Quintana
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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.

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S. Andreon, R. De Propris, E. Puddu, L. Giordano, H. Quintana. 2007-10-04. Scaling relations of the colour-detected cluster RzCS 052 at z=1.016 and of some other high redshift clusters. https://doi.org/10.1111/j.1365-2966.2007.12541.x

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