Vertical Oscillations of Fluid and Stellar Disks

Abstract

A satellite galaxy or dark matter subhalo that passes through a stellar disk may excite coherent oscillations in the disk perpendicular to its plane. We determine the properties of these modes for various self-gravitating plane symmetric systems (Spitzer sheets) using the matrix method of Kalnajs. In particular, we find an infinite series of modes for the case of a barotropic fluid. In general, for a collisionless system, there is a double series of modes, which include normal modes and/or Landau-damped oscillations depending on the phase space distribution function of the stars. Even Landau-damped oscillations may decay slowly enough to persist for several hundred Myr. We discuss the implications of these results for the recently discovered vertical perturbations in the kinematics of solar neighborhood stars and for broader questions surrounding secular phenomena such as spiral structure in disk galaxies.

arXiv comment13 pages, 9 figures, accepted for publication in MNRAS

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• Vertical waves in the solar neighbourhood in Gaia DR2
• A fully cosmological model of a Monoceros-like ring
• Bending Waves in the Milky Way's disc from halo substructure
• The vertical effects of disc non-axisymmetries from perturbation theory: the case of the Galactic bar
• Mapping the Monoceros Ring in 3D with Pan-STARRS1
• Dark matter in galaxies
• Galactoseismology and the Local Density of Dark Matter
• Phase Wrapping of Epicyclic Perturbations in the Wobbly Galaxy
• Spontaneous generation of bending waves in isolated Milky Way-like discs
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• Mapping Milky Way disk perturbations in stellar number density and vertical velocity using Gaia DR3
• On the relevance of chaos for halo stars in the Solar Neighbourhood
• Swing Amplification and the Gaia Phase Spirals
• Wobbly discs -- corrugations seen in the dust lanes of edge-on galaxies
• Kinematics of symmetric Galactic longitudes to probe the spiral arms of the Milky Way with Gaia
• Eigenfunctions of Galactic Phase Space Spirals from Dynamic Mode Decomposition
• On the relevance of chaos for halo stars in the solar neighbourhood II
• First spiral arm detection using dynamical mass measurements of the Milky Way disk
• Gas Dynamics in the Central Molecular Zone and its connection with the Galactic Bar
• Chemodynamical Ages of Small-Scale Kinematic Structures of the Galactic Disc in the Solar Neighborhood from ~250,000 K and M Dwarfs
• Inferring Time-Dependent Distribution Functions from Kinematic Snapshots
• Effects of coplanar satellite bands on galactic disc evolution
• Galactic Surveys in the Gaia Era