Title:
The Formation of Stellar Halos & Their Progenitors
Abstract:
Accreted stellar halos are a natural consequence of galaxy formation in a Lambda-CDM Universe, and contain unique fossil records of hierarchical galaxy formation. The properties of local Milky Way halo stars, however, suggest that the Galaxy’s halo is composed of at least two distinct stellar populations, each exhibiting different spatial distributions, orbits, and metallicities. In this talk I will describe the formation of stellar halos surrounding L* disk galaxies simulated using high-resolution, fully cosmological N-Body + gas dynamical simulations. In particular, I will show that stellar halos form through a process more complex than pure hierarchical accretions, and that this assembly history results in halos with dual stellar populations. I will show how the chemical abundance trends of halo stars can be used to study and identify the observable imprints of the Milky Way's formation history. Using simulations of galaxies two orders of magnitude less massive than the Milky Way, I will discuss new ongoing research to understand the properties of dwarf galaxies, which are the progenitors of the Galactic stellar halo.