Formation, Evolution and Structure of Galaxies

Amongst today's key astronomical questions lies the evolution of galaxies from first light to the present. This is currently one of the most active and fascinating fields in astrophysics. Galaxy evolution is now entering a critical phase with imminent discoveries in the local and the distant universe driven by very large (arrays of) telescopes both on the surface of the Earth as in space. These allow us to probe galaxies at the time they were born (the high redshift universe) as well as study with incredible detail the nearby universe, and recover the fossils leftover from their evolutionary history.

On the theoretical front, we have developed a cosmological model, known as LambdaCDM, that successfully describes a large number of the properties of the Universe. However our understanding of the Universe is far from complete, especially on the scales of galaxies. For example, the LambdaCDM model predicts that roughly 90% of the mass of the Universe is dark, in the form of particles known as cold dark-matter which have yet to be discovered on the Earth.

Researchers at the Kapteyn Astronomical Institute are busy searching for answers to the many open questions in this exciting field. Amongst these:

• When and where did the first stars form? How did they affect the evolution of galaxies?
• How do galaxies accrete their gas? How is their gas content affected by environment and internal processes such as star formation?
• How was the Hubble sequence of galaxies assembled?
• How did the Milky Way and Local Group galaxies form? What can we learn from them about the evolution of galaxies in general?
• What is the nature and distribution of dark matter in galaxies?

Our focus is on aspects of:

• Starburst galaxies and AGN (Barthel)
• Gas and dust content and dynamics of spiral galaxies (Verheijen, van de Hulst, van der Kruit)
• Elliptical galaxies (Koopmans, Peletier, Trager)
• Galaxies in clusters (Koopmans, Trager, Valentijn, Verheijen)
• Stellar populations (Peletier, Tolstoy, Trager, van der Kruit)
• Dwarf galaxies (Helmi, Peletier, Tolstoy)
• The Milky Way (Helmi, Tolstoy)
• Dark matter content and dynamics of galaxies and alternative theories such as MOND (Douglas, Koopmans, Helmi, Verheijen, Sanders)

Faculty active in these areas: Barthel, de Bruyn, Douglas, Helmi, van der Hulst, Koopmans, van der Kruit, Peletier, Tolstoy, Trager, Sanders, Valentijn and Verheijen. Their webpages contain more detailed information on the specific research topics.