The Sunyaev-Zel'dovich Array (SZA)


Introduction

The Interferometric Sunyaev-Zel'dovich Effect Imaging team has successfully observed 27 intermediate redshift and distant galaxy clusters by retrofitting the BIMA and OVRO mm-wave arrays with low-noise HEMT receivers operating from 26 - 36 GHz. These observations have led to high quality images; in addition, these observations are being used to make SZE estimates of cluster gas masses and gas mass fractions and to measure direct cluster distances by combining SZE and X-ray imaging and spectroscopic observations.

Because of the redshift independence of the SZE cluster decrement, a dedicated SZE imaging array would make an ideal instrument for surveying the high redshift universe for massive, collapsed structures. Although the sensitive 30 GHz receivers coupled to the BIMA and OVRO arrays have provided the high signal to noise constraints on the gas distribution of the highest redshift clusters, the SZE Imaging Experiment in its current form is not sufficiently sensitive to carry out a meaningful high redshift cluster survey. Therefore, we are now building a new array optimized for high redshift cluster detection, the Sunyaev-Zel'dovich Array (SZA).

The SZA consists of eight 3.5 m dishes and a digital correlator with 8 GHz bandwidth. It will have low-noise HEMT receivers operating at 26 - 36 GHz and also at 85 - 115 GHz. It will survey approximately 100 times faster than the current fastest SZE imaging system on BIMA, and it will allow us to probe the distant universe for galaxy clusters. The SZA will be operated with the existing six 10.4 m OVRO telecopes to form a novel, powerful, heteorgeneous array. This will initially used for identifying and removing point source contamination from the SZE survey. It will also allow unprecedented imaging of the SZE for distant clusters.

The SZA is funded by a direct grant from the The National Science Foundation with enhancement from 6 to 8 antenna (doubling the number of baselines), and 90 GHz capability made possible by a contribution from the Center for Cosmological Physics.

Further Information

A document describing specific digital correlator configurations for the proposed array in PDF.