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

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.

22 pages, 7 figures