Difference between the standard thermal SZE calculated for A2163 in 2–45 GHz range and integrated in a 1 arcmin² area and the one modified for values E^∗ = 5 × 10^-9 eV (solid line), 3 × 10^-9 eV (dash – 3 dots), 2 × 10^-9 eV (dot-dashed), and 1 × 10^-9 eV (dashed). The sensitivity achievable with SKA in ~30 h (red thick solid line) and in ~260 h (blue thick long-dashed line) are shown (see Carilli 2005).