Sunyaev Zel'dovich observations of a statistically complete sample of galaxy clusters with OCRA-p

TL;DR

This study presents 30 GHz Sunyaev Zel'dovich observations of a complete sample of galaxy clusters, analyzing their properties and scaling relations, and discusses implications for future surveys.

Contribution

First detailed SZ measurements of a complete, X-ray luminous galaxy cluster sample at z > 0.2, with contaminant correction and analysis of scaling relations.

Findings

All clusters show significant SZ effects with y_0 > 1.9x10^-4.

13 out of 17 clusters detected at >3 sigma significance.

Good agreement with self-similar models of cluster formation.

Abstract

We present 30 GHz Sunyaev Zel'dovich observations of a statistically complete sample of galaxy clusters with OCRA-p. The clusters are the 18 most X-ray luminous clusters at z > 0.2 in the ROSAT Brightest Cluster Sample. We correct for contaminant radio sources via supplementary observations with the Green Bank Telescope, also at 30 GHz, and remove a cluster that is contaminated by an unresolved X-ray source. All 17 remaining clusters have central SZ effects with Comptonisation parameter y_0 exceeding 1.9x10^-4, and 13 are detected at significance > 3 sigma. We use our data to examine scalings between y_0 and X-ray temperature, X-ray luminosity, and the X-ray mass proxy Y_X, and find good agreement with predictions from self-similar models of cluster formation, with an intrinsic scatter in y_0 of about 25%. We also comment on the success of the observations in the face of the contaminant source population, and the implications for upcoming cm-wave surveys.