Radial intensity profiles of J = 3-2 CO isotopolog emission lines (solid lines). In the top and bottom panels, α = 10⁻³ and 10⁻⁴, respectively. From left to right: ¹²CO, ¹³ CO, C¹⁸ O. The emission was convolved with a 0.03^′′ resolution beam for disks located at a distance of 150 pc. The dashed lines show the gas surface densities from the hydrodynamical simulations normalized at the emission at ~5 AU. The vertical dashed line indicates the radial location of the planet.