Weak-lensing mass calibration of the Sunyaev-Zel'dovich effect using APEX-SZ galaxy clusters
Journal article, 2019

The use of galaxy clusters as precision cosmological probes relies on an accurate determination of their masses. However, inferring the relationship between cluster mass and observables from direct observations is difficult and prone to sample selection biases. In this work, we use weak lensing as the best possible proxy for cluster mass to calibrate the Sunyaev-Zel'dovich (SZ) effect measurements from the APEX-SZ experiment. For a well-defined (ROSAT) X-ray complete cluster sample, we calibrate the integrated Comptonization parameter, Y-SZ, to the weak-lensing derived total cluster mass, M-500. We employ a novel Bayesian approach to account for the selection effects by jointly fitting both the SZ Comptonization, Y-SZ-M-500, and the X-ray luminosity, Lx-M-500, scaling relations. We also account for a possible correlation between the intrinsic (lognormal) scatter of L-x and Y-SZ at fixed mass. We find the corresponding correlation coefficient to be r = 0.47(-0.35)(+0.24), and at the current precision level our constraints on the scaling relations are consistent with previous works. For our APEX-SZ sample, we find that ignoring the covariance between the SZ and X-ray observables biases the normalization of the Y-SZ-M-500 scaling high by 1-2 sigma and the slope low by similar to 1 sigma, even when the SZ effect plays no role in the sample selection. We conclude that for higher precision data and larger cluster samples, as anticipated from on-going and near-future cluster cosmology experiments, similar biases (due to intrinsic covariances of cluster observables) in the scaling relations will dominate the cosmological error budget if not accounted for correctly.

galaxies: clusters: general galaxies: clusters: intracluster medium

cosmology: observations

methods: statistical

gravitational lensing: weak


A. Nagarajan

University of Cologne

University of Bonn

F. Pacaud

University of Bonn

M. Sommer

University of Bonn

M. Klein

Max Planck Society

Ludwig-Maximilians-Universität München

K. Basu

University of Bonn

F. Bertoldi

University of Bonn

A. T. Lee

University of California at Berkeley

Lawrence Berkeley National Laboratory

P. A. R. Ade

Cardiff University

A. N. Bender

University of Colorado at Boulder

McGill University

D. Ferrusca

National Institute of Astrophysics, Optics and Electronics

N. W. Halverson

University of Colorado at Boulder

Cathy Horellou

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Extragalactic Astrophysics

B. R. Johnson

Columbia University in the City of New York

J. Kennedy

McGill University

R. Kneissl

Atacama Large Millimeter-submillimeter Array (ALMA)

European Southern Observatory Santiago

K. M. Menten

Max Planck Society

C. L. Reichardt

University of Melbourne

C. Tucker

Cardiff University

B. Westbrook

University of California at Berkeley

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 488 2 1728-1759

Subject Categories

Subatomic Physics

Astronomy, Astrophysics and Cosmology

Probability Theory and Statistics



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5/7/2020 1