Dynamical cluster masses from photometric surveys

Monthly Notices of the Royal Astronomical Society, vol. 518, pp. 2640–2650

Abstract

ABSTRACT The masses of galaxy clusters can be measured using data obtained exclusively from wide photometric surveys in one of two ways: directly from the amplitude of the weak lensing signal or, indirectly, through the use of scaling relations calibrated using binned lensing measurements. In this paper, we build on a recently proposed idea and implement an alternative method based on the radial profile of the satellite distribution. This technique relies on splashback, a feature associated with the apocentre of recently accreted galaxies that offers a clear window into the phase-space structure of clusters without the use of velocity information. We carry out this dynamical measurement using the stacked satellite distribution around a sample of luminous red galaxies in the fourth data release of the Kilo-Degree Survey and validate our results using abundance-matching and lensing masses. To illustrate the power of this measurement, we combine dynamical and lensing mass estimates to robustly constrain scalar–tensor theories of gravity at cluster scales. Our results exclude departures from General Relativity of the order of unity. We conclude the paper by discussing the implications for future data sets. Because splashback mass measurements scale only with the survey volume, stage-IV photometric surveys are well-positioned to use splashback to provide high-redshift cluster masses.

Authors 8

1. Omar Contigiani corresponding

   University of Toronto · Canadian Institute for Theoretical Astrophysics

   Affiliation as printed

   Canadian Institute for Theoretical Astrophysics, University of Toronto Toronto, ON, M5S 3H8, Canada

2. Henk Hoekstra Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University , PO Box 9513, NL-2300 AA Leiden, the Netherlands

3. Margot M. Brouwer

   University of Groningen · Institute for Theoretical Physics Amsterdam · University of Amsterdam

   Affiliation as printed

   Institute for Theoretical Physics, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands

   Kapteyn Astronomical Institute, University of Groningen , Landleven 12, NL-9747 AD Groningen, the Netherlands

4. Andrej Dvornik

   Ruhr University Bochum

   Affiliation as printed

   Ruhr-University Bochum, Astronomical Institute, German Centre for Cosmological Lensing , Universitätsstr. 150, D-44801 Bochum, Germany

5. Maria Cristina Fortuna

   University of Toronto · Canadian Institute for Theoretical Astrophysics

   Affiliation as printed

   Canadian Institute for Theoretical Astrophysics, University of Toronto Toronto, ON, M5S 3H8, Canada

6. Cristobál Sifón

   Pontificia Universidad Católica de Valparaíso

   Affiliation as printed

   Instituto de Física, Pontificia Universidad Católica de Valparaíso , Casilla 4059, Valparaíso, Chile

7. Ziang Yan

   Ruhr University Bochum

   Affiliation as printed

   Ruhr-University Bochum, Astronomical Institute, German Centre for Cosmological Lensing , Universitätsstr. 150, D-44801 Bochum, Germany

8. Mohammadjavad Vakili

   University of Toronto · Canadian Institute for Theoretical Astrophysics

   Affiliation as printed

   Canadian Institute for Theoretical Astrophysics, University of Toronto Toronto, ON, M5S 3H8, Canada