Fourier analysis of the surface density of Kepler-16 simulations testing the relevance of self-gravity with increasing Σ₀. Black lines correspond to the Fourier coefficients of the m = 1 modes, normalised to the axisymmetric m = 0 component. Red lines show the m = 2 modes. Simulations where self-gravity is enabled are shown by dotted lines. Fourier analysis is done on the time-averaged surface density over the period of one binary orbit from 15 000 P_AB.