Formation and dynamics of the Galactic disc and halo
type: CreativeWork
description: The treasure trove of recent data from Gaia and spectroscopic surveys has revealed an abundance of features in the Milky Way that must be interpreted dynamically. The disc, the bar, the halo and the satellites are all components of the Galaxy's dynamical system which are able to interact to create, perturb and destroy substructure. By using tailored and cosmological simulations, this substructure can be modelled and interpreted to learn about the formation and past evolution of the Milky Way. A detailed understanding of our own Galaxy's assembly also provides a test for the cosmological models implemented in hydrodynamic simulations of Milky Way analogues. In Chapter 1 I give an overview of the principles of Galactic dynamics which form the foundation of this thesis. I proceed to outline past research into Galactic archaeology in the Milky Way, including studies into its substructure, evolution and accretion history. Chapter 2 is a study of the dynamical effects of the Sagittarius Dwarf Galaxy (Sgr) on stellar streams produced by tidally disrupting globular clusters, with a focus on the GD-1 stream. This reveals a plethora of perturbations that may result from interactions with a massive Sgr, including asymmetry and folding of the tails. In Chapter 3 I run simulations of a stellar halo-like population of particles in the presence of a rotating bar. I show that the bar is capable of trapping stars in its resonances from highly eccentric and inclined orbits. These form overdensities in phase space which closely resemble similar features seen in data from Gaia. Chapter 4 continues to investigate the trapping of halo orbits in resonances with the bar. I develop an analytic toy model of resonant orbits to predict the appearances of action space (J_φ, J_r) and radial phase space (r, v_r). Both this model and test particle simulations successfully predict the appearance of Gaia data in these spaces, in particular the asymmetry in Galactocentric radial velocity v_r. Chapter…
abstract: The treasure trove of recent data from Gaia and spectroscopic surveys has revealed an abundance of features in the Milky Way that must be interpreted dynamically. The disc, the bar, the halo and the satellites are all components of the Galaxy's dynamical system which are able to interact to create, perturb and destroy substructure. By using tailored and cosmological simulations, this substructure can be modelled and interpreted to learn about the formation and past evolution of the Milky Way. A detailed understanding of our own Galaxy's assembly also provides a test for the cosmological models implemented in hydrodynamic simulations of Milky Way analogues. In Chapter 1 I give an overview of the principles of Galactic dynamics which form the foundation of this thesis. I proceed to outline past research into Galactic archaeology in the Milky Way, including studies into its substructure, evolution and accretion history. Chapter 2 is a study of the dynamical effects of the Sagittarius Dwarf Galaxy (Sgr) on stellar streams produced by tidally disrupting globular clusters, with a focus on the GD-1 stream. This reveals a plethora of perturbations that may result from interactions with a massive Sgr, including asymmetry and folding of the tails. In Chapter 3 I run simulations of a stellar halo-like population of particles in the presence of a rotating bar. I show that the bar is capable of trapping stars in its resonances from highly eccentric and inclined orbits. These form overdensities in phase space which closely resemble similar features seen in data from Gaia. Chapter 4 continues to investigate the trapping of halo orbits in resonances with the bar. I develop an analytic toy model of resonant orbits to predict the appearances of action space (J_φ, J_r) and radial phase space (r, v_r). Both this model and test particle simulations successfully predict the appearance of Gaia data in these spaces, in particular the asymmetry in Galactocentric radial velocity v_r. Chapter…
author: Dillamore, Adam
language: eng
keywords: Milky Way, Galactic Dynamics, Galactic Archaeology, Gaia
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/c92fb1b0-f2a3-4d92-9d81-45be0f73bbe5/download
license: https://creativecommons.org/licenses/by/4.0/
date published: 2024-07-12
date modified: 2026-07-22T22:24:14Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.113269