A Comparison of Algorithms for the Construction of SZ Cluster Catalogues

TL;DR

This paper compares twelve algorithms for constructing galaxy cluster catalogues via the Sunyaev-Zel'dovich effect, analyzing their performance on simulations to assess completeness, purity, and reconstruction accuracy.

Contribution

It provides a comprehensive comparison of SZ detection algorithms using detailed simulations, highlighting key issues and uncertainties in cluster catalogue construction.

Findings

Approximately 1000 cluster candidates at |b|>20° with 90% purity.

Astrometric precision around 2 arcminutes.

Photometric uncertainty approximately 30%.

Abstract

We evaluate the construction methodology of an all-sky catalogue of galaxy clusters detected through the Sunyaev-Zel'dovich (SZ) effect. We perform an extensive comparison of twelve algorithms applied to the same detailed simulations of the millimeter and submillimeter sky based on a Planck-like case. We present the results of this "SZ Challenge" in terms of catalogue completeness, purity, astrometric and photometric reconstruction. Our results provide a comparison of a representative sample of SZ detection algorithms and highlight important issues in their application. In our study case, we show that the exact expected number of clusters remains uncertain (about a thousand cluster candidates at |b|> 20 deg with 90% purity) and that it depends on the SZ model and on the detailed sky simulations, and on algorithmic implementation of the detection methods. We also estimate the astrometric precision of the cluster candidates which is found of the order of ~2 arcmins on average, and the photometric uncertainty of order ~30%, depending on flux.