Frequency spectrum in the γ Dor domain after prewhitening with the first twelve frequencies of Table B.1. The highest amplitude peak corresponds to f₁₃ ≃ 18f_orb. The gray (red) line is the estimate of local noise by PERIOD04 (with a box of 0.2 d^-1). The black dots denote the values used to derive the period spacing. The open circle denotes the frequency f₁₉₃ = 1.2350 d^-1, which according to that period spacing value has n_f193 = 39. This last frequency is also very close to 32f_orb.