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

Gemma Luzzi,Gianluca Polenta,Emanuele D’Angelo,Pasquale Mazzotta,Federico De Luca,Filippo Oppizzi,Herve Bourdin,M De Petris,A Ferragamo,F Mayet

doi:10.1051/epjconf/202225700028

Gemma Luzzi, Gianluca Polenta + Show 8 more

Open Access

https://doi.org/10.1051/epjconf/202225700028

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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 (TCMB(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 TCMB(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.

Highlights

The COBE-FIRAS experiment revealed that the average cosmic microwave background (CMB) spectrum is extremely close to a perfect black-body with present-day temperature T0 = 2.7260 ± 0.0013 K [1] and with possible distortions < 10−5
According to the Big Bang model, under the assumptions of adiabatic expansion and photon number conservation, the CMB temperature evolves with redshift z as TCMB(z) = T0(1 + z) which is one of the core predictions of standard big bang cosmology that may be violated under nonstandard scenarios [3]
The possibility of determining TCMB(z), T0 and the monopole of y-type distortion of the CMB spectrum from measurements of the Sunyaev–Zeldovich effect had been suggested long ago [4, 5]. Building upon these two works, in Sect. 2) we present constraints on the CMB temperature evolution with redshift and independent estimate of T0

Summary

Introduction

The possibility of determining TCMB(z), T0 and the monopole of y-type distortion of the CMB spectrum from measurements of the Sunyaev–Zeldovich effect had been suggested long ago [4, 5]. Building upon these two works, in Sect. PR2 temperature maps at frequencies from 100 to 857 GHz [16] For this sample we derive information about the R500 and about the electronic temperature Te, which will be included as prior information in the subsequent analysis for the extraction of the CMB temperature at the redshift of each cluster.

SZ maps at Planck frequencies and modelling of the SZ signal

Constraining the monopole y distortion via the SZ spectrum

Findings

Forecasts for Millimetron