Results of the power-law fitting of the simulated ¹³CO line intensity profiles obtained with the simple power-law models (M_disk = 10⁻⁴ M_⊙ and M_disk = 10⁻² M_⊙ in panels a and b, respectively). The values of the fitted power-law index γ_fit are shown by the filled dots as a function of the radial range over which the fitting was carried out for the high-resolution images (0.01′′ beam). The empty symbols in panel a show the fitted power-law index γ_fit when the simulated images are convolved with a 0.2′′ beam. The model input power-law indexes are shown by the dashed lines. The dotted line shows the starting point of the fitting R_start.