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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.

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


See Astronomy master schedules

You will find the timetables for all courses and degree programmes of Leiden University in the tool MyTimetable (login). Any teaching activities that you have sucessfully registered for in MyStudyMap will automatically be displayed in MyTimeTable. Any timetables that you add manually, will be saved and automatically displayed the next time you sign in.

MyTimetable allows you to integrate your timetable with your calendar apps such as Outlook, Google Calendar, Apple Calendar and other calendar apps on your smartphone. Any timetable changes will be automatically synced with your calendar. If you wish, you can also receive an email notification of the change. You can turn notifications on in ‘Settings’ (after login).

For more information, watch the video or go the the 'help-page' in MyTimetable. Please note: Joint Degree students Leiden/Delft have to merge their two different timetables into one. This video explains how to do this.

Mode of instruction

  • Lectures

  • Exercise classes

Assessment method

Written exam, see the Astronomy master examination schedules.

Reading list

Notes taken during the lectures suffice, but the student may want to consult some textbooks as well. An example of a good one is "Mo, van den Bosch and White, "Galaxy Formation and Evolution", ISBN 978-0521857932. Available from Cambridge University Press" (optional)


From the academic year 2022-2023 on every student has to register for courses with the new enrollment tool MyStudyMap. There are two registration periods per year: registration for the fall semester opens in July and registration for the spring semester opens in December. Please see this page for more information.

Please note that it is compulsory to both preregister and confirm your participation for every exam and retake. Not being registered for a course means that you are not allowed to participate in the final exam of the course. Confirming your exam participation is possible until ten days before the exam.

Extensive FAQ's on MyStudymap can be found here.


Lecturer: Prof.dr. J. Schaye