Measurement of theTCMBevolution from the Sunyaev-Zel’dovich effect

In the standard hot cosmological model, the black-body temperature of the cosmic microwave background (CMB), TCMB, increases linearly with redshift. Across the line of sight CMB photons interact with the hot (~ 107−8 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 TCMB. Using tSZ data from the Planck satellite, it is possible to constrain TCMB below z = 1. Focusing on the redshift dependance of TCMB, we obtain TCMB(z) = (2.726 ± 0.001) × (1 + z)1−β K with β = 0.009 ± 0.017, which improves on previous constraints. Combined with measurements of molecular species absorptions, we derive β = 0.006 ± 0.013. These constraints are consistent with the standard (i.e. adiabatic, β = 0) Big-Bang model.