Measurement of the $T_{\\rm CMB}$ evolution from the Sunyaev-Zel'dovich effect

In the standard hot cosmological model, the black-body temperature of the Cosmic Microwave Background (CMB), $T_{\\rm CMB}$, increases linearly with redshift. Across the line of sight CMB photons interact with the hot ($\\sim10^{7-8}$ K) and diffuse gas of electrons from galaxy clusters. This interaction leads to the well known thermal Sunyaev-Zel'dovich effect (tSZ), which produces a distortion of the black-body emission law, depending on $T_{\\rm CMB}$. Using tSZ data from the ${\\it Planck}$ satellite it is possible to constrain $T_{\\rm CMB}$ below z=1. Focusing on the redshift dependance of $T_{\\rm CMB}$ we obtain $T_{\\rm CMB}(z)=(2.726\\pm0.001)\\times (1+z)^{1-\\beta}$ K with $\\beta=0.009\\pm0.017$, improving previous constraints. Combined with measurements of molecular species absorptions, we derive $\\beta=0.006\\pm0.013$. These constraints are consistent with the standard (i.e. adiabatic, $\\beta=0$) Big-Bang model.