Galactoseismology in cosmological simulations: Vertical perturbations by dark matter, satellite galaxies and gas

Only recently, complex models that include the global dynamics from dwarf satellite galaxies, dark matter halo structure, gas infalls, and stellar disk in a cosmological context became available to study the dynamics of disk galaxies such as the Milky Way (MW). We use a MW model from a high-resoluti...

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Bibliographic Details
Published in:arXiv.org 2023-11
Main Authors: García-Conde, B, Antoja, T, Roca-Fàbrega, S, Gómez, F, Ramos, P, Garavito-Camargo, N, Gómez-Flechoso, MA
Format: Article
Language:English
Subjects:
Astronomical models
Bending
Dark matter
Deposition
Disk galaxies
Dwarf galaxies
Dynamic structural analysis
Evolution
Fourier analysis
Galactic disk
Galactic halos
Historical structures
Misalignment
Perturbation
Satellites
Simulation
Star & galaxy formation
Star formation
Supernovae
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Summary:Only recently, complex models that include the global dynamics from dwarf satellite galaxies, dark matter halo structure, gas infalls, and stellar disk in a cosmological context became available to study the dynamics of disk galaxies such as the Milky Way (MW). We use a MW model from a high-resolution hydrodynamical cosmological simulation named GARROTXA to establish the relationship between the vertical disturbances seen in its galactic disk and multiple perturbations, from the dark matter halo, satellites and gas. We calculate the bending modes in the galactic disk in the last 6 Gyr of evolution. To quantify the impact of dark matter and gas we compute the vertical acceleration exerted by these components onto the disk and compare them with the bending behavior with Fourier analysis. We find complex bending patterns at different radii and times, such as an inner retrograde mode with high frequency, as well as an outer slower retrograde mode excited at different times. The amplitudes of these bending modes are highest during the early stages of the thin disk formation and reach up to 8.5 km s-1 in the late disk evolution. We find that the infall of satellite galaxies leads to a tilt of the disk, and produces anisotropic gas accretion with subsequent star formation events, and supernovae, creating significant vertical accelerations onto the disk plane. The misalignment between the disk and the inner stellar/dark matter triaxial structure, formed during the ancient assembly of the galaxy, creates a strong vertical acceleration on the stars. We conclude that several agents trigger the bending of the stellar disk and its phase spirals in this simulation, including satellite galaxies, dark sub-halos, misaligned gaseous structures, and the inner dark matter profile, which coexist and influence each other, making it challenging to establish direct causality.
ISSN:2331-8422