A comparison of algorithms for the construction of SZ cluster catalogues

¹ DSM/Irfu/SPP, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France
e-mail: jean-baptiste.melin@cea.fr
² Institut d’Astrophysique Spatiale, CNRS et Université de Paris XI, Bâtiment 120-121, Centre Universitaire d’Orsay, 91400 Orsay Cedex, France
³ Institut fur Theoretische Astrophysik, Zentrum fur Astronomie der Universitat Heidelberg, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany
⁴ APC, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
⁵ Université Paris Diderot – Paris 7, 75205 Paris Cedex 13, France
⁶ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
⁷ DSM/Irfu/SAp, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France
⁸ Astrophysics Group, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge, CB3 0HE, UK
⁹ Max-Planck-Institut für extraterrestrische Physik Giessenbachstr, 85748 Garching, Germany
¹⁰ Instituto de Física de Cantabria (CSIC-UC), 39005 Santander, Spain
¹¹ Kavli Institute for Cosmology Cambridge and Institute of Astronomy, Madingley Road, Cambridge, CB3 OHA, UK
¹² ALMA JAO, Av. El Golf 40 – Piso 18, Las Condes, Santiago ; ESO, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago, Chile
¹³ Università di Roma “Tor Vergata”, via della ricerca scientifica, 1, 00133 Roma, Italy
¹⁴ Astronomisches Rechen-Institut, Monchhofstrasse 12-14, 69120 Heidelberg, Germany
¹⁵ Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy

Received: 3 September 2010
Accepted: 3 October 2012

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 arcmin on average, and the photometric uncertainty of about 30%, depending on flux.