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Large Scale Structure and Galaxy Formation


Admission requirements

Familiarity with basic concepts of cosmology is assumed. The student is assumed to have basic knowledge of the thermal history of the universe, recombination, the cosmic microwave background, cosmic distances, horizons, and to be able to work with the Friedmann equation. In terms of the Leiden curriculum, the Astronomy master's course Origin and Evolution of the Universe provides the ideal preparation.


How galaxies and the large-scale structures in which they are embedded form is a fundamental question in extra-galactic astronomy. It is an area that has seen tremendous progress, but is still constantly challenged by ever-improving observational data. This course introduces you to this fascinating subject and the underlying physics, starting from how small density perturbations grow into dark matter haloes, to how baryons cool and form the galaxy population we observe today. It will cover the main theoretical treatment of perturbations, as well as how to interpret the main observational probes of large-scale structure.

Physical concepts are derived from basic principles where possible. The emphasis is on intuitive rather than mathematically rigorous derivations.

Topics that will be covered include:

  • Linear growth of density perturbations

  • Free streaming

  • Transfer functions and the matter power spectrum

  • Non-linear spherical collapse

  • Jeans smoothing

  • Radiation drag

  • Statistical cosmological principle

  • Clustering and biasing

  • Halo mass functions and Press-Schechter theory

  • Scaling laws and virial relations

  • Cosmic web

  • Redshift-space distortions

  • Radiative cooling and its importance

  • Angular momentum and its influence

  • Reionization

  • The Gunn-Peterson effect

  • The thermal history of the intergalactic medium

  • Feedback processes

  • Halo models, semi-empirical models, and simulations

Course objectives

Upon completion of this course you will be able to explain how (we think that) large-scale structures and galaxies form and evolve and you will be able to carry out calculations of the formation of structures in the universe.

Upon completion of the course you will be able to:

  • Compute the growth of density fluctuations

  • Compute the shape of the matter power spectrum

  • Explain the morphology of the cosmic web

  • Explain redshift-space distortions

  • Explain galaxy biasing and clustering

  • Compute halo mass functions using Press-Schechter theory

  • Compute galaxy and halo scaling relations

  • Understand radiative cooling processes

  • Estimate the effect of radiative cooling on galaxy formation

  • Estimate the effect of angular momentum on galaxy formation

  • Model the process of reionization

  • Compute the thermal history of the intergalactic medium

  • Compute Gunn-Peterson absorption

  • Understand the basics of feedback processes in galaxy formation

  • Understand the basics of halo models, semi-empirical models and simulations of galaxy formation

Soft skills

This course is not intended to develop soft skills per se.


See Astronomy master schedules

Mode of instruction

  • Lectures

  • Exercise classes

Assessment method

Written exam, see the Astronomy master examination schedules.


Brightspace will be used to communicate with students and to share lecture slides, homework assignments, and any extra materials. To have access, you need a student ULCN account.

Reading list

Mo, van den Bosch and White, "Galaxy Formation and Evolution", ISBN 978-0521857932. Available from Cambridge University Press, strongly recommended.


Via uSis. More information about signing up for your classes can be found here. Exchange and Study Abroad students, please see the Prospective students website for information on how to apply.

Contact information

Lecturer: Prof. dr. K. (Koen) Kuijken
Assistants: Ronald Timmerman, Christiaan Groeneveld