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Galaxies and Cosmology


Admission requirements

A strong background in physics and mathematics is required. In terms of the Leiden curriculum, the student must have successfully completed the Analyse1NA or Analyse 1, Analyse 2NA or Analyse 2 and Lineare Algebra 1NA or Lineare algebra 1 courses of the first year, as well as Klassieke Mechanica a and Inleiding Astrofysica.


By studying galaxies and cosmology, we ultimately seek to understand how a very smooth universe at early times produced the wealth of structure we see now.

This course studies the application of physics to the understanding of astronomical phenomena related to galaxies and cosmology. We start locally, with our own Milky Way and its components. We then work our way outward to other galaxies in the Local Group and beyond. We then study the large-scale structure of the Universe, and we uncover the mathematics behind the expansion of the Universe. We end by discussing the most distant galaxies and their supermassive black holes.

This diverse range of topics will be understood both qualitatively and quantitatively, with weekly homework to give the students a chance to work through the more difficult concepts.

The following themes are covered:

  • Our Milky Way

  • The interstellar medium

  • Galactic Dynamics

  • Our Local Group

  • Spiral & elliptical galaxies

  • Galaxy groups & clusters

  • The Friedman equation

  • Our expanding universe

  • High-redshift galaxies

  • Supermassive black holes & Active Galactic Nuclei

Course objectives

Upon completion of this course, the student will be able to synthesize information on the diverse range of topics listed above by qualitatively discussing and quantitatively solving a large variety of exercises on these aspects of galaxies & cosmology.

At the end of this course, you will have been trained in the following behavior-oriented skills:

  • Planning and executing your homework assignments on time

  • Critical thinking


See Schedules bachelor Astronomy

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

Mode of instruction

  • Lectures

  • Exercise classes

Assessment method

  • Homework assignments (bonus)

  • Written exam

Reading list

The main textbook for the course will be:

  • Galaxies in the Universe: An Introduction (2nd edition) by Sparke & Gallagher

An additional book that will be used for the lectures covering cosmology is:

  • An Introduction to Modern Cosmology (2nd edition) by Liddle


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. An exemption is the fall semester for 1st year bachelor students, the student administration will enroll this group.

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. H. Hoekstra
Assistants: Chloe Chen, Lucie Rowlands, Jurjan Bootsma


Brightspace is used as the central information source in CMb.
It offers, a.o., an overview of the course material and the program for each week, all powerpoint slides of the lectures, the pre-recorded lectures, the recordings of the live lectures fro reviewing, assignments, and examples of exams of previous years.