Galaxy Structure, Formation and Evolution

The Kapteyn Institute has been deeply involved in the study of galaxies, starting with Jacobus Kapteyn himself, in studying the Milky Way. The study of galaxy formation and evolution still constitutes one of the core research themes at the Institute today.

Galaxy M101 is a typical example of a face-on spiral galaxy. Image credit: NASA, ESA, K. Kuntz (JHU), F. Bresolin (University of Hawaii), J. Trauger (Jet Propulsion Lab), J. Mould (NOAO), Y.-H. Chu (University of Illinois, Urbana), and STScI

How did galaxies form and how did they evolve into their current state? When we look at very distant galaxies, we actually are looking back in time. This allows us to probe samples of galaxies from the moment when they were born, until today. On the other hand, by inspecting the current, local universe (the Milky Way, the Local Group) in full detail, we can also recover the fossils from the evolutionary history.

Observations from the rotation of stars and gas in galaxies, from the motion of galaxies in clusters and from the universe as a whole, all indicate that a significant fraction, 90%, of the mass of the Universe must be in a non-radiating form. This so-called dark matter is thought to be in the form of particles that yet have to be discovered on Earth.

Some of the key questions driving galaxy structure, formation and evolution research include:

How do galaxies form during the earliest phases in the Universe?
How do galaxies evolve over cosmic time and form the range of galaxy types currently observed?
What is the role of dark matter and (HI) gas in the formation of galaxies?

Galaxies are build up through mergers. This is an artist impression of a galaxy eating a small satelite galaxy. The individual stars will be smeared into streaks on the sky, called stellar streams. Identifying stellar streams allows us to reconstruct the formation history of the Milky Way. Image credit: Jon Lomberg

Thousands of galaxies flood this near-infrared image of galaxy cluster SMACS 0723. High-resolution imaging from the James Webb Space Telescope combined with a natural effect known as gravitational lensing made this finely detailed image possible. Image credit: NASA/ESA/CSA/STScI

Some of the projects, programs and instruments in galaxy research in which the institute is involved:

The study of high-z galaxies with the JWST, HST, VLT, ALMA, and other world-class facilities
The study of the dynamics of our MW and other galaxies with,e.g., Gaia, WEAVE
The Fornax Deep Survey
The XSL stellar library
The study of weak and strong gravitational lensing with e.g. VST-KiDS, HST, Keck, ALMA and Euclid
The study of HI in galaxies with, e.g., APERTIF, MeerKAT, SKA
Milky Way foreground studies with LOFAR

The future of galaxy-evolution research at the Kapteyn Institute is based on the scientific exploitation of new facilities that are becoming available this decade, as well as capitalizing on current developments, such as the studies of the Epoch of Reionization with LOFAR and APERTIF HI studies. Kapteyn astronomers are highly involved in JWST, particularly via the MIRI European Guaranteed Time, which will allow them to study galaxy evolution since very early cosmic times. These analyses will be complemented with larger-area galaxy studies with Euclid, which will be launched in 2023. In addition, further projects on the physics of galaxy formation from the Epoch of Reionization to the Local Universe will be conducted using ground-based facilities, such as WEAVE/WHT and different instruments (MICADO, MOSAIC) on the E-ELT.

Scientific staff working in this field are Caputi, Dayal, Helmi, van der Hulst, Fraternali, Koopmans, McKean, Oosterloo, Peletier, Starkenburg, Tolstoy, Trager, Valentijn, Verheijen, Wang, van de Weijgaert

Last modified:

13 December 2022 3.07 p.m.