Deriving the Hubble constant using Planck and XMM-Newton observations of galaxy clusters

TL;DR

This paper presents a new Bayesian method combining Planck and XMM-Newton data to accurately estimate the Hubble constant from galaxy cluster observations, reducing biases and errors.

Contribution

It introduces a Bayesian approach that integrates simulation-informed priors with high-quality observational data to improve Hubble constant measurements.

Findings

H_0=67 ± 3 km s^{-1} Mpc^{-1} from 61 galaxy clusters

Reduced biases from cluster triaxiality and clumpiness

Enhanced accuracy using spatially resolved SZ and X-ray data

Abstract

The possibility of determining the value of the Hubble constant using observations of galaxy clusters in X-ray and microwave wavelengths through the Sunyaev Zel\'dovich (SZ) effect has long been known. Previous measurements have been plagued by relatively large errors in the observational data and severe biases induced, for example, by cluster triaxiality and clumpiness. The advent of \textit{Planck} allows us to map the Compton parameter y, that is, the amplitude of the SZ effect, with unprecedented accuracy at intermediate cluster-centric radii, which in turn allows performing a detailed spatially resolved comparison with X-ray measurements. Given such higher quality observational data, we developed a Bayesian approach that combines informed priors on the physics of the intracluster medium obtained from hydrodynamical simulations of massive clusters with measurement uncertainties. We apply our method to a sample of 61 galaxy clusters with redshifts up to z < 0.5 observed with Planck and XMM-Newton observations and find H_0=67 \pm 3 km s^{-1} Mpc^{-1}.