📝 SummarXiv

Abstract

Kinematic information is crucial for understanding the evolution of complex systems, such as interstellar gas. Obtaining full 3D kinematic information is a crucial final step for modeling and interpretation. Molecular clouds are nurseries where stars are born. Stars at a very early stage, like young stellar objects (YSOs), inherit the spatial and kinematic structure of the gas patches they originate from. In this paper, we combine measurements of radial velocities towards the gas and the kinematic information of YSOs from Gaia DR3 to derive 3D velocities of a sample of YSO (Young Stellar Object)-MC (Molecular Cloud) complexes at d$\lesssim$3.5kpc from the Sun. We find that the molecular interstellar medium traced by the YSO-MC complexes generally follows Galactic rotation, with an additional peculiar velocity of 8.6 km s$^{-1}$. The random motion of these complexes in the Galactic XY plane is more energetic than motion along the Z direction. A catalogue containing the 3D velocities of the YSO-MC complexes at different reference frames is available, and the distances and 3D velocities of well-known molecular clouds are presented. Our results set the foundation for exploring the interplay between the Galaxy, the molecular ISM, and star formation. Data available at https://doi.org/10.5281/zenodo.16364877.