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Course unit
ASTROPHYSICS OF GALAXIES
SCN1032594, A.A. 2018/19
Information concerning the students who enrolled in A.Y. 2018/19
ECTS: details
Type |
Scientific-Disciplinary Sector |
Credits allocated |
Core courses |
FIS/05 |
Astronomy and Astrophysics |
6.0 |
Course unit organization
Period |
First 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 |
Examination board
Board |
From |
To |
Members of the board |
6 Commissione Astrofisica delle Galassie 18-19 |
01/10/2018 |
30/11/2019 |
CORSINI
ENRICO MARIA
(Presidente)
PIZZELLA
ALESSANDRO
(Membro Effettivo)
CASOTTO
STEFANO
(Supplente)
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Prerequisites:
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Fundamentals of Astronomy, Astrophysics, Physics, and Numerical Methods. |
Target skills and knowledge:
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Knowledge of the galactic structure and mass distribution using stellar dynamics in combination with photometric and kinematical data obtained from ground and space-based observations. Ability to compare theoretical predictions from the fundamental equations of stellar hydrodynamics with observational data. |
Examination methods:
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Oral exam on different topics discussed during lectures. |
Assessment criteria:
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The student will be asked to use a correct terminology to describe the structure of galaxies, know the full program of the course, link the different topics discussed during lectures, properly compare observational data with theoretical predictions, and solve problems. |
Course unit contents:
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1) Overview of the properties of galaxies: Morphology. Photometry. Kinematics. Scaling relations.
2) Potential theory: Gravitational potential. Poisson equation. Laplace equation. Gauss theorem. Potential energy. Potential energy tensor. Spherical systems. Newton theorems. Point mass. Homogeneous sphere. Hubble density profile. Power-law density profile. Axisymmetric systems. Logarithmic potential.
3) 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 two-dimensional non-axisymmetric non-rotating potential. Loop and box orbits. Stable and unstable orbits. Orbits in a two-dimensional nonaxisymmetric rotating potential. Jacobi integral. Lagrangian points. Corotation. Families of orbits x1, x2, x3, x4. Introduction to the orbits in a three-dimensional triaxial potential.
4) Collisionless systems: Geometric collisions. Strong collisions. Weak collisions. Crossing time. Relaxation time. Distribution function. Collisionless Boltzmann equation. Continuity equation. Euler equation. Jeans equations. Applications of the Jeans equations. Velocity ellipsoid. Asymmetric drift. Mass density in the Solar neighborhood. Velocity dispersions in spherical systems. Mass-anisotropy degeneracy. Spheroidal systems with isotropic velocity dispersions. Disk heating mechanisms. Virial theorem. Mass-to-light ratio of spherical systems. Rotation of elliptical galaxies. Jeans' theorem. Density profile from the distribution function. Spherical systems with isotropic velocity dispersion. Polytropes. Plummer sphere. Isothermal sphere. Singular isothermal sphere. King radius. King method to derive the mass-to-light ratio. King models. Tidal radius. Concentration parameter. Distribution function from the density profile. Eddington equation. Introduction to spherical systems with anisotropic velocity dispersion. Michie models. |
Planned learning activities and teaching methods:
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Lectures at the blackboard and with the help of PowerPoint presentations on galactic structure and dynamics. Lectures are given in Italian. |
Additional notes about suggested reading:
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All the slides of the lectures are available through the website of the course on the e-learning platform of the Department of Physics and Astronomy "G. Galilei" (https://elearning.unipd.it/dfa/). Suggested textbook. |
Textbooks (and optional supplementary readings) |
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Binney J., Tremaine S., Galactic Dynamics. Princeton, NJ: Princeton University Press, 1987.
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Innovative teaching methods: Teaching and learning strategies
- Loading of files and pages (web pages, Moodle, ...)
Innovative teaching methods: Software or applications used
- Moodle (files, quizzes, workshops, ...)
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