PHY3144 Galaxies and Observational Cosmology

2007-2008

Code: PHY3144
Title: Galaxies and Observational Cosmology
Instructors: Dr Suzanne Aigrain
CATS credits: 10
ECTS credits: 5
Availability: unrestricted
Level: 3
Pre-requisites: N/A
Co-requisites: N/A
Background Assumed: -
Duration: Semester I
Directed Study Time: 22 lectures
Private Study Time: 78 hours
Assessment Tasks Time: -
Observation report: 2002/03 RJH

Aims

This module covers the physics of large-scale objects in the universe from star clusters, galaxies and quasars to the structure of the universe itself. The fascination that these objects hold is due in part to the enormous range of physical processes which play a role in their formation and evolution including Newtonian and general relativistic gravitation, fluid dynamics, magnetic fields, radiation, and nucleosynthesis. These objects are studied at a more advanced level than in PHY2019 and the course is intended to complement PHY3142 which covers the small-scale universe (e.g. stellar astrophysics). Many of the topics discussed are applicable to a wide range of astrophysical processes. For example, a significant fraction of the course covers gravitational dynamics which is applicable to star formation, the evolution of star clusters, galaxies, clusters of galaxies, and the formation of large-scale structure in the universe.

Specific aims of the module are for students to: (1) develop a detailed knowledge of the physical processes involved in the formation and evolution of star clusters, galaxies and the universe; (2) be able to apply this knowledge to calculate the evolution of some of the simpler systems and qualitatively understand the complex systems.

Intended Learning Outcomes

Students should be able to:

Module Specific Skills

• describe in detail the structure and constituents of galaxies, quasars and the universe;
• calculate gravitational orbits of objects in various systems;
• derive characteristic size and timescales for the evolutionary processes in clusters, galaxies and the universe;
• discuss how and why the objects covered form and evolve in time and space;

Discipline Specific Skills

• solve mathematical problems;
• apply knowledge of physical processes to understand astronomical objects;

Personal and Key Skills

• develop self-study skills;
• work in order to meet deadlines.

Learning and Teaching Methods

Lectures (20×1hr), guided reading, and problems classes (2×1hr).

Assignments

Problem sheets to be completed as homework.

Assessment

One 90-minute examination (100%).

Syllabus Plan and Content

1. Our Galaxy
   1. Introduction to the structure and constituents of our Galaxy. Size; Disc, halo and bulge; Population I and II stars; Star clusters; Differential rotation.
   2. Disc, spheriodal components, Galactic centre. Gas (atomic, molecular) and dust; Spiral structure; Star formation; Bulge; Halo; MACHO; Galactic centre and central black hole.
2. Star Clusters and Stellar Dynamics
   1. Two and three-body problems; Orbits in smooth potentials; Epicyclic and harmonic motion. Orbits in complicated potentials; Bars; Collisionless stellar systems.
   2. Virial theorem. Conservative forces, potential energy; Poisson equation.
   3. Dynamical evolution of stellar systems. Globular clusters; Relaxation; Mass segregation; Core collapse; Effect of a central black hole; Evaporation; Tidal disruption.
3. Galaxies
   1. Morphological types. Hubble types; Luminosity functions.
   2. Sprial and irregular galaxies. Freeman's law; Rotation curves; Dark matter; Tully-Fisher relation; Mass-to-light ratios; Black hole masses; Spiral structure and density waves.
   3. Elliptical galaxies. Kormendy relation; Faber-Jackson relation; Velocity dispersion.
   4. Galaxy evolution. Luminosities; Stellar populations; Chemical evolution.
   5. Galaxy interactions and the intergalactic medium. Interactions; Starbursts; Fountains.
   6. Active Galactic Nuclei (AGN) and quasars. Observations and models; Unified model of AGN; Evolution and space density of quasars.
4. Observational Cosmology
   1. Geometry of the Universe. Euclidean and curved spaces, Robertson-Walker metric; Expansion; Redshift; Hubble law; Angular diameter-distance relation.
   2. Dynamical evolution of the Universe. Friedmann models - open, closed, Einstein-de Sitter; Parameters of the universe.
   3. The big bang. Physics of the early universe; Time line; Matter and radiation dominated eras; Cosmic microwave radiation, Planck, acoustic modes; Inflation, baryogenesis, primodial nucleosynthesis.
5. Large-scale Structure, Clusters of Galaxies, and Galaxy Formation
   1. Clusters of galaxies. Local group, Virgo, Coma clusters; Local mass density; Peculiar velocities; Cluster masses, X-ray emitting gas, cooling flows; Dark matter, lensing, distances, Sunyaev-Zeldovich effect.
   2. Structure formation. Hot and cold dark matter; Numerical simulations; Lyman-alpha forest.
   3. Galaxy formation and star formation rate. ELS; Searle and Zinn; Dark matter and dissipational collapse; Bulge and disc formation.

Core Text

Not applicable

Supplementary Text(s)

Bertin G. (1999), Dynamics of Galaxies, Cambridge University Press, ISBN 0-521-47855-3 (UL: 523.112 BER)
Binney J. and Tremaine S. (1988), Galactic Dynamics, Princeton University Press, ISBN 0-691-08445-9 (UL: 523.112 BIN)
Combes F., Boisse P., Mazure A., Blanchard A. and Seymour M. (1995), Galaxies and Cosmology, Springer-Verlag, ISBN 3-540-58933-3 (UL: 523.112 COM)
Fang L. Z. and Ruffini R. (eds) (1985), Galaxies, Quasars and Cosmology, World Scientific, ISBN 9-971-50083-3 (UL: 523.1 FAN)

Formative Mechanisms

This module is supported by problems classes. Students are able to monitor their own progress by attempting problems sheets provided in the lectures. Students with specific problems should first approach their tutor, and if the problem is not resolved, the lecturer.

Evaluation Mechanisms

The module will be evaluated using information gathered via the student representation mechanisms, the staff peer appraisal scheme, and measures of student attainment based on summative assessment.