Constraining the Milky Way potential using the dynamical kinematic substructures

TL;DR

This paper introduces a method to constrain the Milky Way's gravitational potential by analyzing stellar kinematic substructures in phase-space, linking them to orbital families and frequency space to identify the true potential.

Contribution

The authors develop a technique that uses orbital frequency analysis of stellar kinematics to accurately determine the Galaxy's non-axisymmetric potential components.

Findings

Dynamical substructures are best preserved in the true gravitational potential.

Frequency maps reveal clear structures associated with orbital families.

Method effectively constrains the Milky Way's non-axisymmetric potential components.

Abstract

We present a method to constrain the potential of the non-axisymmetric components of the Galaxy using the kinematics of stars in the solar neighborhood. The basic premise is that dynamical substructures in phase-space (i.e. due to the bar and/or spiral arms) are associated with families of periodic or irregular orbits, which may be easily identified in orbital frequency space. We use the "observed" positions and velocities of stars as initial conditions for orbital integrations in a variety of gravitational potentials. We then compute their characteristic frequencies, and study the structure present in the frequency maps. We find that the distribution of dynamical substructures in velocity- and frequency-space is best preserved when the integrations are performed in the "true" gravitational potential.