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 ( \sim 10 ^ { 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 _ { 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 \pm 0.001 ) \times ( 1 + z ) ^ { 1 - \beta } K with \beta = 0.009 \pm 0.017 , which improves on previous constraints .
Combined with measurements of molecular species absorptions , we derive \beta = 0.006 \pm 0.013 .
These constraints are consistent with the standard ( i.e .
adiabatic , \beta = 0 ) Big-Bang model .