Theoretical Astrophysics

Course content

This fundamental course provides an overview of some of the most important astrophysical processes that shape the evolution, and observational properties, of astrophysical systems, from planets to stars, and from supermassive black holes to entire galaxies.  The course is strongly recommended for all students starting at the M.Sc. and Ph.D. levels in preparation for their further study and research in any area of astrophysics, including planetary sciences and cosmology.  We will cover the basic equations, learn how to solve them, and understand their implications.  This course will provide students with a wide range of interests in observational, theoretical, or computational astrophysics with a valuable toolkit to become more competent researchers.

The aim of this course is to bring together several key concepts in physics and build upon them in order to understand some of the most important processes in astrophysics. This is crucial in order to understand the formation and evolution of a wide range of astrophysical systems. This is a demanding task that is possible to accomplish by attending the lectures and investing the time in doing the weekly homework assignments. This course has been designed in such a way that lectures and weekly assignments come together to achieve the goals sets forth.

Content: This course gives an introduction to, and builds upon, the following subjects:

  • Order of magnitude astrophysics, fundamental concepts and equations
  • Radiative processes: basic radiative transfer, absorption, scattering
  • Hydrodynamics: fundamental equations, waves, instabilities, shocks
  • Magnetohydrodynamics: fundamental equations, waves, instabilities
  • Gravity: virial theorem for N-body and gases, self-gravitating fluids
  • Astrophysical flows: basic properties of disks, jets, and winds

MSc Programme in Physics

MSc Programme in Physics with a minor subject

Learning outcome

When the course is finished it is expected that the student is able to:

  • Identify the physical processes involved in a given astrophysical setting
  • Carry out order of magnitude calculations to support physical intuition
  • Solve basic problems involving radiative transfer, wave propagation, instabilities, and shocks in hydrodynamics and magnetohydrodynamics.


When the course is finished it is expected that the student is able to:

  • Explain the basic astrophysical processes covered by the course content
  • Explain how these processes act together to dictate the dynamics of astrophysical flows such as self-gravitating fluids, disk, winds, and jets.


This course will endow the students with a powerful set of tools that will allow them to work more confidently on a wide variety of subjects in astrophysics. The competences acquired in this course are a valuable complement to those obtained in observational and phenomenological astrophysics courses. These competences are an indispensable asset for students wishing to pursue studies in any branch of astrophysics. This course provides the students with the background knowledge to pursue research in this field and is an excellent preparation for a M.Sc. project.

The lectures will usually be given in the blackboard. There will be weekly assignments. Students that choose not to hand in the assignments can still take the exam. However, investing the time in doing these exercises is considered to be a crucial part of the learning experience for this course and the points gathered from these do carry 1/3 of the final grade. Most of the exercises will be analytical and there could be some computer exercises that could be done using Matlab, Mathematica, Python, or other program or language that the students find useful.

See Absalon for final course material. The following is an example of expected course literature.


There is no mandatory book for the course. The lectures draw upon several books but mostly follow the spirit of

  • Theoretical Astrophysics. Vol. 1., Astrophysical Processes.

   T. Padmanabhan. Cambridge University Press. 2000.

This is an excellent book for the theoretically inclined students, but it might be rather advanced for students to read it on their own. The lectures that draw from this book are prepared to make the material accessible. If you like to see the book before you decide whether to buy it, you can have a look at the copy in the NBI library, or just stop by M. Pessah’s office. You are also welcome to send an email with inquiries.

Some students could find other books at the library useful, e.g.,

  • Principles of Astrophysical Fluid Dynamics, Clarke and Carswell, Cambridge University Press. 2014.
  • The Physics of Fluids and Plasmas, An Introduction to Astrophysics., A. R. Chouduri. Cambridge University Press. 1998.

  • Theoretical Astrophysics, An Introduction, M. Bartelmann, Wiley-VCH, 2013

Students will benefit from being acquainted with basic concepts in Calculus, Mechanics, Electrodynamics, Thermodynamics and Statistical Physics. Knowledge about fluid dynamics is welcome but not essential. Students who would like to take the course but could benefit from brushing up their knowledge in these and related subjects are encouraged to contact M. Pessah in advance in order to discuss useful reading material toward this end.

Academic qualifications equivalent to a BSc degree is recommended.

7,5 ECTS
Type of assessment
Continuous assessment
Written examination, 4 hours under invigilation
Type of assessment details
The final grade will be based on two components:
(i) weekly homework assignments (1/3 of the final grade)
(ii) 4-hour written exam (2/3 of the final grade)
These elements do not have to be passed separately.
All aids allowed
Marking scale
7-point grading scale
Censorship form
No external censorship
several internal examiners

4 hour written exam, counts for 100% of the final grade.

Criteria for exam assessment

see learning outcome

Single subject courses (day)

  • Category
  • Hours
  • Lectures
  • 36
  • Preparation
  • 130
  • Exercises
  • 36
  • Exam
  • 4
  • English
  • 206


Course number
7,5 ECTS
Programme level
Full Degree Master

1 block

Block 1
No limitation
The number of seats may be reduced in the late registration period
Study Board of Physics, Chemistry and Nanoscience
Contracting department
  • The Niels Bohr Institute
Contracting faculty
  • Faculty of Science
Course Coordinator
  • Martin Elias Pessah   (7-74776c7a7a686f4775697035727c356b72)

Martin Pessah, 35 32 53 12, Bygning B, 01-1-Bb6
Irene Tamborra
Daniel D'Orazio

Saved on the 16-08-2023

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