Constraining the evolution of the CMB temperature with SZ measurements from Planck data

TL;DR

This study measures the CMB temperature at various redshifts using Planck data to test the standard cosmological model, finding results consistent with the predicted temperature-redshift relation within a 3% precision.

Contribution

It provides the first precise measurement of T_CMB(z) for a large sample of galaxy clusters using Planck SZ data, constraining deviations from the standard law.

Findings

Deviations from T_CMB(z)=T_0(1+z) are limited to beta=0.022 +/- 0.018.

Combined data yields beta=0.016 +/- 0.012, consistent with standard cosmology.

Measurements cover redshifts from 0.01 to 0.94, with up to 3% precision.

Abstract

The CMB temperature-redshift relation, T_CMB(z)=T_0(1+z), is a key prediction of the standard cosmology, but is violated in many non standard models. Constraining possible deviations to this law is an effective way to test the LambdaCDM paradigm and to search for hints of new physics. We have determined T_CMB(z), with a precision up to 3%, for a subsample (104 clusters) of the Planck SZ cluster catalog, at redshift in the range 0.01-- 0.94, using measurements of the spectrum of the Sunyaev Zel'dovich effect obtained from Planck temperature maps at frequencies from 70 to 353 GHz. The method adopted to provide individual determinations of T_CMB(z) at cluster redshift relies on the use of SZ intensity change, Delta I_SZ(nu), at different frequencies, and on a Monte-Carlo Markov Chain approach. By applying this method to the sample of 104 clusters, we limit possible deviations of the form T_CMB(z)=T_0(1+z)^(1-beta) to be beta= 0.022 +/- 0.018, at 1 sigma uncertainty, consistent with the prediction of the standard model. Combining these measurements with previously published results we get beta=0.016+/-0.012.