
Course unit
GALAXY DYNAMICS
SCN1035990, A.A. 2017/18
Information concerning the students who enrolled in A.Y. 2017/18
ECTS: details
Type 
ScientificDisciplinary Sector 
Credits allocated 
Core courses 
FIS/05 
Astronomy and Astrophysics 
6.0 
Course unit organization
Period 
Second semester 
Year 
1st Year 
Teaching method 
frontal 
Type of hours 
Credits 
Teaching hours 
Hours of Individual study 
Shifts 
Lecture 
6.0 
48 
102.0 
No turn 
Start of activities 
26/02/2018 
End of activities 
01/06/2018 
Examination board
Board 
From 
To 
Members of the board 
4 Commissione 
01/10/2017 
30/09/2018 
CORSINI
ENRICO MARIA
(Presidente)
GALLETTA
GIUSEPPE
(Membro Effettivo)
PIZZELLA
ALESSANDRO
(Supplente)

Prerequisites:

Basic knowledge of Physics, Astronomy, Astrophysics, and Numerical Analysis. 
Target skills and knowledge:

The course is devoted to study of the galactic structure using stellar dynamics in combination with photometric and kinematical data obtained from ground and spacebased observations. 
Examination methods:

Oral exam. 
Assessment criteria:

Knowledge of the topics discussed during the lectures. 
Course unit contents:

1. OVERVIEW OF THE PROPERTIES OF GALAXIES. Morphology. Photometry. Kinematics. Scaling relations.
2. POTENTIAL THEORY. Gravitational potential. Poisson’s equation. Laplace’s equation. Gauss’ theorem. Potential energy. Potential energy tensor. Spherical systems. Newton’s theorems. Point mass. Homogeneous sphere. Hubble density profile. Powerlaw density profile. Axisymmetric systems. Logarithmic potential.
3. THE ORBITS OF THE STARS. Costants and integrals of the motion. Surfaces of section. Orbits in a static spherical potential. Orbits in a Keplerian potential. Orbits in a static axisymmetric potential. Motion in the meridional plane. Nearly circular orbits. Epicyclic approximation. Orbits in a twodimensional nonaxisymmetric nonrotating potential. Loop and box orbits. Stable and unstable orbits. Orbits in a twodimensional nonaxisymmetric rotating potential. Jacobi’s integral. Lagrange’s points. Corotation. Families of orbits x1, x2, x3, x4. Introduction to the orbits in a threedimensional triaxial potential.
4. COLLISIONLESS SYSTEMS. Geometric collisions. Strong collisions. Weak collisions. Crossing time. Relaxation time. Distribution function. Collisionless Boltzmann equation. Continuity equation. Euler’s equation. Jeans’ equations. Applications of the Jeans’ equations. Velocity ellipsoid. Asymmetric drift. Mass density in the Solar neighborhood. Velocity dispersions in spherical systems. Massanisotropy degeneracy. Spheroidal systems with isotropic velocity dispersions. Disk heating mechanisms. Virial theorem. Masstolight ratio of spherical systems. Rotation of elliptical galaxies. Jeans’ theorem. Density profile from the distribution function. Spherical systems with isotropic velocity dispersion. Polytropes. Plummer’s sphere. Isothermal sphere. Singular isothermal sphere. King’s radius. King’s method to derive the masstolight ratio. King’s models. Tidal radius. Concentration parameter. Distribution function from the density profile. Eddington’s equation. Introduction to spherical systems with anisotropic velocity dispersion. Michie’s models. 
Planned learning activities and teaching methods:

Lectures on topics of galactic dynamics. 
Additional notes about suggested reading:

All the slides of the lectures are available in the Moodle website of the course. 
Textbooks (and optional supplementary readings) 

Binney J., Tremaine S., Galactic Dynamics. Princeton, NJ: Princeton University Press, 1987.


