The Massive and Distant Clusters of WISE Survey

SZ effect of Verification with the Atacama Compact Array – Localization and Cluster Analysis

¹ Max-Planck-Institut für Astrophysik (MPA), Karl-Schwarzschild-Strasse 1, Garching 85741, Germany
e-mail: lucadim@mpa-garching.mpg.de
² European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, Garching 85748, Germany
³ Space Research Institute, Profsoyuznaya 84/32, Moscow 117997, Russia
⁴ Astronomical Institute of the Czech Academy of Sciences, Prague Bǒcní II 1401/1A, 14000 Praha 4, Czech Republic
⁵ Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611, USA
⁶ Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110, USA
⁷ Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
⁸ Department of Physics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA

Received: 25 February 2020
Accepted: 15 April 2020

Abstract

Context. The Massive and Distant Clusters of WISE Survey (MaDCoWS) provides a catalog of high-redshift (0.7 ≲ z ≲ 1.5) infrared-selected galaxy clusters. However, the verification of the ionized intracluster medium, indicative of a collapsed and nearly virialized system, is made challenging by the high redshifts of the sample members.

Aims. The main goal of this work is to test the capabilities of the Atacama Compact Array (ACA; also known as the Morita Array) Band 3 observations, centered at about 97.5 GHz, to provide robust validation of cluster detections via the thermal Sunyaev–Zeldovich (SZ) effect.

Methods. Using a pilot sample that comprises ten MaDCoWS galaxy clusters, accessible to ACA and representative of the median sample richness, we infer the masses of the selected galaxy clusters and respective detection significance by means of a Bayesian analysis of the interferometric data.

Results. Our test of the Verification with the ACA – Localization and Cluster Analysis (VACA LoCA) program demonstrates that the ACA can robustly confirm the presence of the virialized intracluster medium in galaxy clusters previously identified in full-sky surveys. In particular, we obtain a significant detection of the SZ effect for seven out of the ten VACA LoCA clusters. We note that this result is independent of the assumed pressure profile. However, the limited angular dynamic range of the ACA in Band 3 alone, short observational integration times, and possible contamination from unresolved sources limit the detailed characterization of the cluster properties and the inference of the cluster masses within scales appropriate for the robust calibration of mass–richness scaling relations.