Experimental research in the astrophysics group focuses on near-field cosmology, in which local galaxies are studied as examples to understand the properties of the Universe, including dark matter and dark energy. We particularly focus on the dynamics and structure of the Milky Way as revealed by large, international photometric and spectroscopic surveys such as the Sloan Digital Sky Survey (SDSS) and the Large Area Multi-Object Spectroscopic Telescope (LAMOST), and by astrometric surveys such as Gaia. Dwarf galaxies are ripped apart by tidal forces in the Milky Way into tidal streams. These streams are used to constrain the processes by which the Milky Way galaxy formed, and the distribution of the dark matter within it. The dwarf galaxies also excite wavelike structures in the Milky Way disk that could explain how spiral galaxy structure is formed and sustained.