PSD of high-pass filtered (R_c = 100) planet spectrum (T = 500 K, log(g) = 4, [M/H] = 0) for two different resolutions on the total spectral range offered by BT-Settl spectra (0.3–12 µm). The hatched areas correspond to the areas under the curves equal to the quantity α². Note: the PSD has been smoothed only for better visualization purposes. The y-axis is relative to the total flux of the companions. Only the ratios between the curves explaining the a variation from a given resolution to another one should be taken into consideration.