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Information about the course:

PAP317 Galactic dynamics (Galaksien dynamiikka)

Lecturers: Prof. Peter Johansson (Room D311)

Course assistants:  M.Sc. Matias Mannerkoski (Room D315) & Dr. Shihong Liao (Room D325)

Lectures: Tuesdays 14.15-16.00. Due to the Corona virus situation this course will be organised as an online course, with all lectures given over Zoom. The  problem sets will be appear on the course homepage and the problem set answers are to be returned in Moodle.

Problem sessions: Thursdays 14.15-16.00 on Zoom, every 2-3 weeks on the following dates: 4.2, 18.2, 4.3, 25.3, 15.4, 6.5
First lecture on 19.1. – Final lecture on 4.5

First lecture on 19.1.2021 and last lecture on 4.5.2021

  • In total 14 lectures covering various aspects of Galactic dynamics. The course will directly follow the textbook Galactic Dynamics by Binney&Tremaine. Additional material supporting the lecture notes will be included on this website.
  • Problem sets will appear on the course homepage every two weeks. Each problem set will contain 5 questions totalling 6x5=30 questions.
  • The minimum requirement for the problem sets a is 1/3 of the total points, surplus points will result in bonus points for the exam.

Course material:    

  • The course material will consist of handouts closely following the material in the following textbook:
    B&T: J. Binney & S. Tremaine: Galactic Dynamics, Second Edition, Princeton University Press, 2008

  • Additional material can be found in the following books:
    G. Bertin: Dynamics of Galaxies, Cambridge Univ Press, 2000.
    H. Mo, F. van den Bosch & S. White: "Galaxy formation and evolution", Cambridge Univ. Press, 2010
    M. Longair: "Galaxy formation", 2nd ed. Springer, 2008
    Sparke&Gallagher: “Galaxies in the Universe”, 2nd ed. Cambridge Univ Press, 2007

Final exam:

  • The final exam will be held on Tuesday 11.5.2021 at 10.00-14.30. The exam will be an open book home exam, with the answers returned by email.

Course syllabus:

Lecture 1: 19.01.2021: "Introduction to galactic dynamics" B&T pages: 1-5, 33-37, 55-60 + 775-778

  • Introduction to stellar and galactic systems
  • Collisionless systems and the relaxation time
  • Potential theory, Basic definitions and concepts

Lecture 2: 26.01.2021: "Potential theory" B&T pages: 60-77 + 775-778

  • Potentials of Spherical systems
  • The Plummer model
  • Potentials of Flattened systems

Lecture 3: 02.02.2021: "The Milky Way potential and Poisson solvers" B&T pages: 110-118, 122-137

  • The Milky Way potential
  • Direct summation
  • Tree codes
  • Particle-mesh codes

Lecture 4: 09.02.2021: "Orbits in static spherical potentials and axisymmetric potentials" B&T pages: 142-164

  • Orbits in Spherical potentials
  • Orbits in axisymmetric potentials
  • Surfaces of section

Lecture 5: 16.02.2021: "Orbits in axisymmetric and non-axisymmetric potentials" B&T pages: 164-188 + 797-798

  • Nearly circular orbits: epicycles and the velocity ellipsoid
  • Two-dimensional non-rotating potential
  • Two-dimensional rotating potential

Lecture 6: 23.02.2021: "Orbits in non-axisymmetric potential and numerical orbit integration" B&T pages: 188-211 +799-805

  • Weak bars
  • Symplectic integrators
  • Leapfrog integrators
  • Regularisation

Lecture 7: 02.03.2021: "The collisionless Boltzmann equation and the distribution function of spherical systems" B&T pages: 274-283, 287-299

  • The Collisionless Boltzmann Equation
  • Distribution functions for isotropic spherical systems
  • Ergodic distribution functions for systems


Lecture 8: 16.03.2021: "Distribution functions for anisotropic spherical systems and the Jeans equations" B&T: pages: 299-312, 338-349

  • Spherical systems defined by distribution function
  • Particle-based and orbit-based models
  • The Jeans Equations

Lecture 9: 23.03.2021: "The Jeans and Virial equations and Stellar kinematics as a mass detector" B&T: pages: 349-370

  • The Jeans Equations for spherical and axisymmetric systems
  • The Tensor and Scalar Virial theorems
  • Detecting black holes with stellar kinematics

Lecture 10: 30.03.2021: "Choice of equilibrium and stability of collisionless systems" B&T: pages: 370-386, 394-400

  • Extended mass distributions of elliptical galaxies
  • Phase mixing and violent relaxation
  • Linear response theory
  • Linearised equations for stellar and fluid systems

Lecture 11: 13.04.2021: "Stability of collisionless systems" B&T: pages: 401-417

  • The physical basis of the Jeans instability
  • The response of a homogeneous fluid system
  • The response of a homogeneous stellar system

Lecture 12: 20.04.2021: "Disk Dynamics and spiral structure" B&T: pages: 456-480

  • Fundamentals of spiral structure
  • The geometry of spiral arms
  • Angular-momentum transport by spiral-arm torques

Lecture 13: 27.04.2021: "Kinetic theory" B&T: pages: 554-573

  • Relaxation processes.
  • General kinetic results.
  • The thermodynamics of self-gravitating systems.

Lecture 14: 04.05.2021: "Mergers of galaxies and galaxy formation" B&T: pages: 639-655, 674-678, 695-710

  • Dynamical friction and its application.
  • Tidal radii and tidal forces.
  • Galaxy mergers and the structure of merger remnants.
  • Galaxy formation and galaxies in a cosmological setting.

Problem sets:

Final results and course grading:

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