Power spectra of the radial velocity for the simulation ref obtained from MUSIC (top left) and the theoretical prediction using Eq. (36) with the dependence on frequency, ω⁻ⁿ, which varies: n = 4 (top right), n = 3 (bottom left), and n = 5 (bottom right). The angular degree is fixed at ℓ = 5. For the theoretical spectra, a minimal threshold is set at a value of 10⁻⁷ for better visibility.