Evolution of the Y₅₀₀-M₅₀₀ relation. Left: the WMAP data from Fig. 4 are divided into three redshift bins: z < 0.08 (blue diamonds), 0.08 < z < 0.18 (green crosses), z > 0.18 (red triangles). We observe the expected trend: at fixed mass, Y₅₀₀ decreases with redshift. This redshift dependence is mainly due to the angular distance (Y₅₀₀ ∝ D_ang(z)^-2). The stars give the prediction of the model. Right: we divide Y₅₀₀ by and plot it as a function of z to search for evidence of evolution in the Y₅₀₀−M₅₀₀ relation. The thick bars give the 1σ statistical errors from WMAP data. The thin bars give the total 1 sigma errors.