Contamination of the Central Sunyaev--Zel'dovich Decrements in AMiBA Galaxy Cluster Observations

TL;DR

This study assesses how cosmic microwave background anisotropies and radio sources contaminate Sunyaev--Zel'dovich effect measurements in galaxy clusters, affecting the accuracy of SZ flux density estimates.

Contribution

It quantifies contamination levels from primary anisotropies and radio sources in SZ observations and proposes correction methods for these effects.

Findings

Primary anisotropies contribute 13%-50% of SZ flux density.

Radio source contamination ranges from 3%-60%.

Contamination exceeds thermal noise in all observed cases.

Abstract

We investigate the contamination of the Sunyaev--Zel'dovich (SZ) effect for six galaxy clusters, A1689, A1995, A2142, A2163, A2261, and A2390, observed by the Y. T. Lee Array for Microwave Background Anisotropy during 2007. With the range of baselines used, we find that the largest effect (of order 13%-50% of the central SZ flux density) comes from primary anisotropies in the cosmic microwave background and exceeds the thermal noise in all six cases. Contamination from discrete radio sources is estimated to be at a level of (3%-60%) of the central SZ flux density. We use the statistics of these contaminating sources to estimate and correct the errors in the measured SZ effects of these clusters.