Cold Dark Matter Substructure and Galactic Disks
Stelios Kazantzidis
Center for Cosmology and Astro-Particle Physics (CCAPP), Ohio State
November 23, 2009, 4PM, Steward N210
Over the past two decades, the Cold Dark Matter
(CDM) cosmological model has evolved into the prevailing paradigm for
interpreting the formation and evolution of structure in the Universe. In
recent years, theoretical studies set within the CDM cosmogony have
revealed that the dark matter halos of galaxies contain substantial
amounts of substructure in the form of distinct, self-bound entities
or subhalos, and that close encounters between massive substructures
and galactic disks are commonplace throughout cosmic history. The large
number of dark matter subhalo impacts expected over the lifetime of a
galaxy raises interesting questions about the dynamical evolution and even
the survivability of disk galaxies. In this talk, using high-resolution
numerical simulations, I will investigate the effects of halo substructure
on galactic disks in the context of the CDM paradigm. In the process, I
will demonstrate that subhalo bombardment severely perturbs the galactic
disks and imprints a wealth of distinctive morphological and dynamical
signatures on their structure and kinematics. These findings highlight
the significant role of halo substructure in setting the structure of
disk galaxies and driving galaxy evolution. Upcoming galactic structure
surveys and astrometric satellites may be able to distinguish between
competing cosmological models by testing whether the detailed structure
of galactic disks is as excited as predicted by the CDM paradigm.
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