Related papers: A 6-d View of Stellar Shells
The structure, kinematics and dynamics of the Galactic stellar halo are reviewed including evidence of substructure in the spatial distribution and kinematics of halo stars. Implications for galaxy formation theory are subsequently…
Recent observational and theoretical work suggests that the formation of the Galactic stellar halo involved both dissipative processes and the accretion of subfragments. With present data, the fraction of the halo for which an accretion…
The Milky Way contains several distinct old stellar components that provide a fossil record of its formation. We can understand their spatial distribution and kinematics in a hierarchical formation scenario by associating the proto-galactic…
I discuss various proposed formation scenarios for the metal-poor components of the Milky Way Galaxy, emphasising the stellar halo and the thick disk. Interactions and accretion played a significant role in Galactic evolution, in particular…
The evolution of galaxies results from a combination of internal and external processes. The star formation is an internal process transforming cold and dense cores of molecular clouds to stars. It may be triggered internally by expanding…
We present a summary of our recent work on the vertical distribution of the resolved stellar populations in six low mass, edge-on, spiral galaxies observed with the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS). In each…
Stellar photometry obtained using the Hubble Space Telescope is used to study the distributions of the number densities of stars of various ages in 12 irregular and dwarf spiral galaxies viewed edge-on. Two subsystems can be distinguished…
Recent observational constraints restrict the strict applicability of stellar dynamics in spirals to a few rotation periods. However, stellar dynamics concepts such as periodic orbits are invaluable for understanding the various dynamical…
The Galactic halo has a complex assembly history, which can be seen in its wealth of kinematic and chemical substructure. Globular clusters lose stars through tidal interactions with the Galaxy and cluster evaporation processes, meaning…
The star formation history of a galaxy, explicitely here our Milky Way Galaxy, where the most detailed information is attainable, is the convolution of two functions. One function describes the rate of formation of the stars which are today…
The relics of disrupted satellite galaxies around the Milky Way and Andromeda have been found, but direct evidence of a satellite galaxy in the early stages of being disrupted has remained elusive. We have discovered a dwarf satellite…
In hierarchical structure formation, dark matter halos that merge with larger halos can persist as subhalos. These subhalos are likely hosts of visible galaxies. While the dense halo environment rapidly strips subhalos of their dark mass,…
Using high-resolution N-body simulations we study the stellar properties of dwarf spheroidal galaxies resulting from the tidally induced morphological transformation of disky dwarfs on a cosmologically motivated eccentric orbit around the…
Collisions of main sequence stars occur frequently in dense star clusters. In open and globular clusters, these collisions produce merger remnants that may be observed as blue stragglers. Detailed theoretical models of this process require…
In a hierarchical merging scenario, the outer parts of a galaxy are a fossil record of the galaxy's early history. Observations of the outer disks and halos of galaxies thus provide a tool to study individual galaxy histories and test…
Dissipative phenomena occurring during the orbital evolution of a dwarf satellite galaxy around a host galaxy may leave signatures in the star formation activity and signatures in the colour magnitude diagram of the galaxy stellar content.…
Stellar bars are a common morphological feature of spiral galaxies. While it is known that they can form in isolation, or be induced tidally, few studies have explored the production of stellar bars in galaxy merging. We look to investigate…
We present a new model for the formation of stellar halos in dwarf galaxies. We demonstrate that the stars and star clusters that form naturally in the inner regions of dwarfs are expected to migrate from the gas rich, star forming centre…
I review the properties of the Galaxy's stellar halo, specifically as traced by horizontal branch stars, but with reference to and in comparison with other stellar tracers. I discuss the halo density profile, the variation in horizontal…
Our Milky Way Galaxy is a typical large spiral galaxy, representative of the most common morphological type in the local Universe. We can determine the properties of individual stars in unusual detail, and use the characteristics of the…