PHY2019 Observing the Universe

2007-2008

Code: PHY2019
Title: Observing the Universe
Instructors: Prof. M.J. McCaughrean
CATS credits: 10
ECTS credits: 5
Availability: not if PHY3132 already taken (first delivery in 2002/3)
Level: 2
Pre-requisites: N/A
Co-requisites: N/A
Background Assumed: N/A
Duration: Semester II
Directed Study Time: 22 lectures
Private Study Time: 78 hours
Assessment Tasks Time: -
Observation report: 2003/04 ASP

Aims

This module will give students a basic understanding of the universe and its contents, and good understanding of astrophysical measurement. As such it is crucial for the astrophysics project work, and when combined with the detailed understanding of stars, galaxies and cosmology gained in PHY3142 and PHYM432 will produce a well balanced grounding in astrophysics.

The specific aims of the module are to impart: a basic knowledge of the hierarchy of objects in the universe, including their structural and evolutionary relationship to each other; an understanding the underlying principles of key instrumentation used for observational astrophysics; an understanding of how we can obtain structural information and physical parameters from distant, often unresolved, objects.

Intended Learning Outcomes

Students should be able to:

Module Specific Skills

• describe the scale of various structure in the universe and how astrophysicists arrive at these measurements;
• calculate the distances to various objects given suitable data;
• describe the basic functioning of the optical/UV/IR telescope and spectrograph, and radio interferometer;
• discuss how we measure accurate masses and radii of stars;
• discuss the basic evolution of galaxies;
• describe the concepts of expanding space-time and cosmological redshift;
• discuss the role of critical density in determining the type of universe we live in, and its evolution, and describe the predictions of current theories concerning evolution of the early universe;

Discipline Specific Skills

• solve mathematical problems;

Personal and Key Skills

• develop self-study skills;
• work to deadlines.

Learning and Teaching Methods

Lectures, e-learning resources.

Assignments

Problem sheets to be completed as homework.

Assessment

One 90-minute examination (100%).

Syllabus Plan and Content

1. Introductory Survey
   1. Gauging the cosmos.
      Astronomical Objects. Solar system, stars, galaxies. Typical dimensions and distances. Structure and dimensions of our galaxy. Structure of the Universe. Age of the Universe and the Earth.
   2. Distance Measurement 1.
      Outline of big bang-model. City lights analogy. Parallax method, Hipparchos and Space Telescope. Moving-cluster method.
   3. Distance Measurement 2.
      Statistical-parallax method. Apparent and absolute luminosity. Distance modulus. Spectroscopic method (Hertzsprung-Russell diagram).
   4. The Expanding Universe.
      Cepheid variables. Distance of galaxies using standard candles. Tully-Fisher relation for clusters of galaxies. Hubble's law and age of the Universe. Look-back time.
   5. Astronomical Measurements.
      Windows in the Earth's atmosphere. Optical telescopes. Optical spectroscopy. Radio telescopes. IR, UV and X rays.
2. Topics in Stellar and Galactic Evolution
   1. An outline of stellar evolution.
      Importance of mass for lifetimes, luminosities and end points. What is a compact object? White dwarfs, electron degeneracy pressure. Supernovae neutron stars and pulsars.
   2. Measuring stellar masses.
      The observed mass function, brown dwarfs, extra-solar planets.
   3. Measuring stellar radii.
      Direct methods. Visual binaries. Spectroscopic binaries.
   4. Black holes.
      Proving compactness - light travel time and X-ray astronomy; introduction to accretion discs.
   5. Basic nucleosynthesis.
      Slow and rapid processes. Chemical enrichment of ISM; Population I and Population II.
   6. A brief introduction to Galaxies.
      Galaxy types. Rotation curves, missing mass and spiral arms. Quasars. Clusters.
3. Cosmology
   1. Expansion of the Universe.
      Rubber-sheet analogy. Cosmological principle. Co-moving objects. Cosmic scaling factor, co-moving coordinates.
   2. Recession velocity.
      Velocity-Distance Relation. Expansion and the velocity-distance law. Hubble sphere, cosmic horizon, observable universe. Hubble period, age of universe. Deceleration. Types of universe.
   3. Redshifts.
      Doppler redshift. Gravitational redshift. Expansion redshift. Multiple redshifts.
   4. Evolution of the universe.
      Radiation-dominated era. Matter-dominated era. 3 K cosmic background, anomalies. Critical density. Early universe.
   5. Types of Universe.
      Expanding cosmic ball. Flat universes. Curved universes. Steady-state universe. Einstein-de Sitter universe.

Core Text

Not applicable

Supplementary Text(s)

Harrison E.R. (1981), Cosmology: the Science of the Universe, Cambridge University Press, ISBN 0-521-22981-2 (UL: 523.1 HAR/X)
Kraus L.M. , The Physics of Start Trek, Perennial, ISBN 0-006-55042-8 (UL: Ordered 30.8.05)
Smith R.C. (1995), Observational Astrophysics, CUP, ISBN 0-521-27834-1 (UL: On order)

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.