The Effects of Radial Migration on the Vertical Structure of Galactic Discs

TL;DR

This study shows that internal spiral perturbations cause disc thickening through heating and radial migration, affecting stellar populations' structure and aligning with observations of the Milky Way.

Contribution

It provides new evidence that radial migration and internal heating jointly influence disc thickening and vertical structure in isolated galactic discs.

Findings

Disc thickens due to internal processes and radial migration.

Vertical velocity dispersions depend on stellar age and radius change.

Results qualitatively match recent Milky Way observations.

Abstract

We present evidence that isolated growing discs, subject to internal spiral perturbations, thicken due to both heating \emph{and} radial migration. We show this by demonstrating that the thickness and vertical velocity dispersions of coeval stars depend on their age as well as the change in their radii. While the disc thickens due to internal processes, we find that this induces only a minor amount of flaring. We further demonstrate the consequences of such thickening on the structural properties of stellar populations and find that they qualitatively agree with recent studies of the Milky Way disc.