Visibility analyses for DM Tau (Sect. 3; Appendix B). Data points in the upper and lower panels show the real part of the m=0 moment (monopole) of the complex visibilities and the amplitudes of the m=1 moment of the complex visibilities, respectively. Error bars were calculated by the standard deviation at each radial bin of the uv-space. Red lines show the smoothed data points using the Savitzky-Golay filter (length of the filter window=7, order of the polynomial=2). Blue lines in each panel show 100 Savitzky–Golay filter smoothed random realization of noises (note that visibility amplitudes are positive definite). Green line in the upper panel shows the best-fit of the 0^th order Bessel function of the first kind (J₀).