3D test particle simulations of the Galactic disks. The kinematical effects of the bar

TL;DR

This study uses 3D test particle simulations to analyze how a rotating galactic bar influences the kinematic distributions of stars in both the thin and thick disks across various Galactic regions and heights.

Contribution

It provides new insights into the long-term and transient kinematic effects of a galactic bar on different stellar disk populations through detailed numerical simulations.

Findings

Bar affects velocity distributions of disk stars.

Transient effects last about 10 bar rotations.

Bar imprints are detectable vertically up to 1-2 kpc.

Abstract

Aims: To study the imprints of a rotating bar on the kinematics of stars in the thin and thick disks throughout the Galaxy. Methods: We perform test particle numerical simulations of the thin and thick disks in a 3D Galactic potential that includes a halo, a bulge, thin and thick disks, and a Ferrers bar. We analyze the resulting velocity distributions of populations corresponding to both disks, for different positions in the Galaxy and for different structural parameters of the bar. Results: We find that the velocity distributions of the disks are affected by the bar, and that strong transient effects are present for approximately 10 bar rotations after this is introduced adiabatically. On long (more realistic) timescales, the effects of the bar are strong on the kinematics of thin disk stars, and weaker on those in the thick disk, but in any case significant. Furthermore, we find that it is possible to trace the imprints of the bar also vertically and at least up to z ~ 1 kpc for the thin disk and z ~ 2 kpc for the thick disk.