Measurement of the T_CMB evolution from the Sunyaev-Zel’dovich effect

¹ Institut d’Astrophysique Spatiale, CNRS (UMR8617) Université Paris-Sud 11, Bâtiment 121, 91405 Orsay Cedex, France
e-mail: ghurier@ias.u-psud.fr
² CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
³ Université de Toulouse, UPS-OMP, IRAP, 31400 Toulouse, France

Received: 9 September 2013
Accepted: 27 November 2013

Abstract

In the standard hot cosmological model, the black-body temperature of the cosmic microwave background (CMB), T_CMB, 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 T_CMB. Using tSZ data from the Planck satellite, it is possible to constrain T_CMB below z = 1. Focusing on the redshift dependance of T_CMB, we obtain T_CMB(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.