Galaxies

Galaxies are groups of millions or billions of stars, and are central to our understanding of the Universe we live in. The provide the location for the birth, life and death of all stars, including our own Sun which lies in the Milky Way galaxy. On the largest scales, galaxies provide the 'test particles' used by cosmologists to map the size, expansion rate and evolution of the entire universe. This course will lead the student through the growth in our understanding of galaxies that occurred through both observations and theoretical insights throughout the 20th century, and will highlight the many intriguing mysteries remaining to be tackled by astronomers. The course will make use of an interactive CD-ROM, video and photographic film material which students can use to undertake investigations in their own homes.

Qualification gained:

A Certificate of Professional Development in Astronomy will be awarded for the successful completion of both modules. Each module is assigned 12 credit points which can be used to build up credits towards other academic qualifications at Liverpool John Moores University and other Universities.

We provide:

CD-ROM and necessary course software, course video, photographic material, astronomy support for the duration of the course (by post, email, telephone, internet telephone and fax) , news group for student discussion, and a course website.

You need:

Good access to a computer with CD-ROM player. The computer needs to be able to run an internet browser which we can supply though it is not essential for it to be connected the internet.

Commitment:

The course lasts for four months. We expect that during a typical week you will need to spend 30 minutes watching course video material, 1 to 2 hours on computer and/or photographic exercises, 45 minutes reviewing the relevant material on the CD-ROM and in your textbook and doing multiple choice questions and 10 mins in correspondence with tutor. Overall we expect that you will put around 120 hours of time into the course.

Assessment:

You need to email, post or fax us your work for the course. The weighting for the marking will be as follows: Coursework assignments (75%), End of module examination (25%). The usual rate for the submission of assignments will be approximately one per month.

Course Contents:

1: Galaxy classification
Spiral, elliptical and dwarf galaxies. The Hubble `Tuning fork' diagram and its development into modern classification systems.

2: What are galaxies made of?
Description of the typical contents of spiral and elliptical galaxies: Stars (young and old), gas (molecules, atoms and ultra-high-temperature plasmas), dust, magnetic fields, dark matter, black holes.

3: Multi-wavelength imaging of galaxies
Optical appearance of spiral and elliptical galaxies compared and contrasted with imaging at other wavelengths- radio, infrared, ultraviolet, x-ray and gamma-ray. What do these various wavelengths tell us? The disc of our Milky Way galaxy as a test case.

4: Types of stars in galaxies from spectroscopy
What is spectroscopy, and what can it tell us about galaxies? Emission and absorption lines- what they are and where they come from. Spectral classification of young and old populations of stars, spectral indicators of star formation.

5: Distances and rotation rates of galaxies from spectroscopy
The Doppler shift. Galaxy redshifts and the expansion of the Universe. The Hubble constant. Galaxy rotation curves, gravitational attraction, and the evidence for missing mass in galaxies- `Dark Matter'.

6: Star formation in galaxies
The types of galaxies which are still forming stars, and where this activity occurs within galaxies. Effects which trigger star formation, including spiral arms; near-misses, collisions and merging impacts between galaxies; central bars; and supernova-triggered star formation.

7: Galaxy formation
What do young galaxies look like, and what are the methods used to find them? Evidence for evolution in the properties of galaxies from the distant, early Universe to the present day.

8: The effect of environments on galaxies
The link between galaxy shapes and the local environments in which they live- rich clusters of many hundreds of galaxies, loose groups, or total isolation. Possible effects of nearby neighbours on galaxies like our Milky Way- interactions, mergers, removal of gas, infall of dwarf galaxies,- and how these processes shape the galaxies we observe.

9: Black holes in galaxies.
Observational evidence for supermassive (a million to a billion times the mass of the Sun) black holes in the centres of our neighbouring galaxies. Possible links between these black holes and quasar activity early in the history of the Universe. Active black holes in nearby galaxies.