Jointly fitting weak lensing, X-ray and Sunyaev-Zel'dovich data to constrain scalar-tensor theories with clusters of galaxies

TL;DR

This paper develops a framework to jointly analyze weak lensing, X-ray, and Sunyaev-Zel'dovich data from galaxy clusters to constrain scalar-tensor theories, specifically DHOST models, by deriving their effects on observable cluster properties.

Contribution

It derives theoretical expressions for cluster observables within DHOST theories and demonstrates how combined measurements can constrain both cluster and gravity model parameters.

Findings

Combined measurements can effectively constrain DHOST parameters.

Fisher forecasts show potential for future surveys to test scalar-tensor theories.

Deviations from General Relativity are quantifiable through cluster observables.

Abstract

Degenerate higher-order scalar-tensor (DHOST) theories are considered the most general class of scalar-tensor theories so that any constraints on them apply to the full set of scalar-tensor models. DHOST theories modify the laws of gravity even at galaxy clusters scale hence affecting the weak lensing (WL), X-ray and Sunyaev-Zel'dovich observables. We derive the theoretical expression for the lensing convergence $\kappa$, and the pressure profile $P$, of clusters in the framework of DHOST theories, and quantify how much they deviate from their General Relativity (GR) counterparts. We argue that combined measurements of $\kappa$, $P$, and of the electron number density, $n_e$, can constrain both the cluster and DHOST theory parameters. We carry on a Fisher matrix forecasts analysis to investigate whether this is indeed the case considering different scenarios for the spatial resolution and errors on the measured quantities.