Observability of the vertical shear instability in protoplanetary disk CO kinematics

Context. Dynamical and turbulent motions of gas in a protoplanetary disk are crucial for their evolution affect planet formation. Recent observations suggest weak turbulence the disk's outer regions. However, physical mechanism these regions remains uncertain. The vertical shear instability (VSI) is promising to produce disks. Aims. Our aim study observability velocity structure produced by VSI via CO kinematics with ALMA. Methods. We perform global 3D hydrodynamical simulations VSI-unstable disk. post-process simulation results radiative transfer calculations, synthetic predictions rotational emission lines. Following, we compute line sight map, its deviations from sub-Keplerian equilibrium solution. explore detectability identifying kinematic signatures using realistic simulated observations. Results. show steady state dynamics great detail. From infer stress value $\alpha_{r\phi}=1.4 \times 10^{-4}$. On large scales, observe 50 m s$^{-1}$ as axisymmetric rings. find optimal conditions at $i \lesssim 20^{\circ}$ trace structures VSI. found that current diagnostics constrain non-thermal broadening not applicable anisotropic turbulence. Conclusions. detection possible Observations including an extended antenna configuration combined highest spectral resolution available needed robust detection. characterization large-scale perturbations required level