Cosmology with the SZ spectrum: Measuring the Universe’s temperature with galaxy clusters

Abstract

The hot gas in clusters of galaxies creates a distinctive spectral distortion in the cosmic microwave background (CMB) via the Sunyaev-Zel’dovich (SZ) effect. The spectral signature of the SZ can be used to measure the CMB temperature at cluster redshift ( T CMB ( z )) and to constrain the monopole of the y -type spectral distortion of the CMB spectrum. In this work, we start showing the measurements of T CMB ( z ) for a sample extracted from the Second Catalog of galaxy clusters produced by Planck (PSZ2) and containing 75 clusters selected from CHEX-MATE. Then we show the forecasts for future CMB experiments about the constraints on the monopole of the y-type spectral distortion of the CMB spectrum via the spectrum of the SZ effect.