# Analysis of the Amplitude of the Sunyaev-Zel'dovich Effect out to Redshift z=0.8

## TL;DR

This study investigates how the Sunyaev-Zel'dovich effect's amplitude varies with redshift and mass in galaxy clusters up to z=0.8, using Planck and SDSS data to analyze cluster properties and their evolution.

## Contribution

It provides new measurements of SZ amplitude dependence on mass and redshift, and examines dust emission, CMB temperature evolution, and mass estimation biases in galaxy clusters.

## Key findings

- SZ amplitude is proportional to M^{2.70+/-0.37} or M^{2.51+/-0.38}
- Cluster dust has emissivity index beta~2 and temperature T~25 K
- Cluster mass estimates are biased by a factor of (1+z)^{-1.8}

## Abstract

The interaction of the cosmic microwave background (CMB) with the hot gas in clusters of galaxies, the so-called Sunyaev--Zel'dovich (SZ) effect, is a very useful tool that allows us to determine the physical conditions in such clusters and fundamental parameters of the cosmological models. In this work, we determine the dependence of the the SZ surface brightness amplitude with redshift and mass of the clusters. We have used PLANCK+IRAS data in the microwave-far infrared and a catalog with >10^5 clusters of galaxies extracted from the SDSS by Wen et al. (2012). We estimate and subtract the dust emission from those clusters. From the residual flux, we extract its SZ flux densities. The absolute value of the SZ amplitude indicates that the gas mass is around 10% of the total mass for cluster masses of M~10^{14} M_sun. This amplitude is compatible with no evolution with redshift and proportional to M^{2.70+/-0.37} (using X-ray derived masses) or M^{2.51+/-0.38} (using weak-lensing derived masses), with some tension regarding the expectations of the self-similar dependence (amplitude proportional to M^{5/3}). Other secondary products of our analysis include that clusters have a dust emission with emissivity index beta~2 and temperature T~25 K; we confirm that the CMB temperature agrees with a dependence of T_0(1+z) with clusters of much lower mass than those explored previously; and we find that the cluster masses derived by Wen et al. (2012) from a richness-mass relationship are biased by a factor of (1+z)^{-1.8} with respect to the X-ray and weak-lensing measurements.