Joint cosmology and mass calibration from tSZ cluster counts and cosmic shear

TL;DR

This paper introduces a joint analysis method combining tSZ cluster counts and cosmic shear to improve cosmological constraints and cluster mass calibration, demonstrating significant gains over traditional approaches.

Contribution

It develops a halo model framework for joint inference from tSZ and cosmic shear data, including their correlations and non-Gaussian covariance, to enhance cosmological and mass calibration constraints.

Findings

Factor two improvement in dark energy figure of merit.

Most mass calibration info from large/intermediate scales.

Constraints comparable to traditional stacked lensing methods.

Abstract

We present a new method for joint cosmological parameter inference and cluster mass calibration from a combination of weak lensing measurements and the abundance of thermal Sunyaev-Zel'dovich (tSZ) selected galaxy clusters. We combine cluster counts with the spherical harmonic cosmic shear power spectrum and the cross-correlation between cluster overdensity and cosmic shear. These correlations constrain the cluster mass-observable relation. We model the observables using a halo model framework, including their full non-Gaussian covariance. Forecasting constraints on cosmological and mass calibration parameters for a combination of LSST cosmic shear and Simons Observatory tSZ cluster counts, we find competitive constraints for cluster cosmology, with a factor two improvement in the dark energy figure of merit compared to LSST cosmic shear alone. We find most of the mass calibration information will be in the large and intermediate scales of the cross-correlation between cluster overdensity and cosmic shear. Finally, we find broadly comparable constraints to traditional analyses based on calibrating masses using stacked cluster lensing measurements, with the benefit of consistently accounting for the correlations with cosmic shear.