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 \Lambda CDM 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 \pm 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 \pm 0.012 .