Orbital tori for non-axisymmetric galaxies

Abstract

Our Galaxy's bar makes the Galaxy's potential distinctly non-axisymmetric. All orbits are affected by non-axisymmetry, and significant numbers are qualitatively changed by being trapped at a resonance with the bar. Orbital tori are used to compute these effects. Thick-disc orbits are no less likely to be trapped by corotation or a Lindblad resonance than thin-disc orbits. Perturbation theory is used to create non-axisymmetric orbital tori from standard axisymmetric tori, and both trapped and untrapped orbits are recovered to surprising accuracy. Code is added to the TorusModeller library that makes it as easy to manipulate non-axisymmetric tori as axisymmetric ones. The augmented TorusModeller is used to compute the velocity structure of the solar neighbourhood for bars of different pattern speeds and a simple action-based distribution function. The technique developed here can be applied to any non-axisymmetric potential that is stationary in a rotating from - hence also to classical spiral structure.

21 pp, 18 figs, accepted by MNRAS

References in corpus (9)

• The Structure of the Milky Way's Bar Outside the Bulge
• Constraining the Galaxy's dark halo with RAVE stars
• NMAGIC: Fast Parallel Implementation of a Chi-Squared-Made-to-Measure Algorithm for Modelling Observational Data
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• Bringing the Galaxy's dark halo to life
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• Managing resonant trapped orbits in our Galaxy
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• Solar System Migration Points to a Renewed Concept: Galactic Habitable Orbits
• Quantifying the influence of bars on action-based dynamical modelling of disc galaxies
• Quantifying torque from the Milky Way bar using Gaia DR2
• Resolving local and global kinematic signatures of satellite mergers with billion particle simulations
• Wrinkles in Time. II. Stellar Age Trends in Kinematic Signatures from Transient Spiral Structure