Galaxy Clusters at z>=1: Gas Constraints from the Sunyaev-Zel'dovich Array

TL;DR

This study measures the gas content of galaxy clusters at redshift z>=1 using Sunyaev-Zel'dovich effect data, confirming the presence of hot gas in some distant clusters and establishing upper limits for others, thus advancing understanding of cluster evolution.

Contribution

First application of SZ effect measurements to high-redshift clusters with gas constraints, demonstrating detection capabilities and consistency with lower-redshift scaling relations.

Findings

SZ effect detected in clusters with gas masses > 10^13 Msun.

IR-selected clusters show no SZ detection, indicating low gas masses.

Results consistent with self-similar scaling relations at high redshift.

Abstract

We present gas constraints from Sunyaev-Zel'dovich (SZ) effect measurements in a sample of eleven X-ray and infrared (IR) selected galaxy clusters at z >=1, using data from the Sunyaev-Zel'dovich Array (SZA). The cylindrically integrated Compton-y parameter, Y , is calculated by fitting the data to a two-parameter gas pressure profile. Where possible, we also determine the temperature of the hot intra-cluster plasma from Chandra and XMM-Newton data, and constrain the gas mass within the same aperture (r_2500 ) as Y . The SZ effect is detected in the clusters for which the X-ray data indicate gas masses above ~ 10^13 Msun, including XMMU J2235-2557 at redshift z = 1.39, which to date is one of the most distant clusters detected using the SZ effect. None of the IR-selected targets are detected by the SZA measurements, indicating low gas masses for these objects. For these and the four other undetected clusters, we quote upper limits on Y and Mgas_SZ , with the latter derived from scaling relations calibrated with lower redshift clusters. We compare the constraints on Y and X-ray derived gas mass Mgas_X-ray to self-similar scaling relations between these observables determined from observations of lower redshift clusters, finding consistency given the measurement error.