My OpenLearn Profile
Personalise your OpenLearn profile, save your favourite content and get recognition for your learning
Introduction to active galaxies
The field of active galaxies is recognised as one of increasing importance. But how do we know there are different kinds of galaxy? What are active galaxies? How are they powered? This free course, Introduction to active galaxies, examines the different types of active galaxies and looks at the crucial role of the active galactic nucleus and the energy source at its heart.
Course learning outcomes
After studying this course, you should be able to:
- explain how and why the optical spectrum of an active or starburst galaxy differs from that of a normal galaxy
- explain how and why the broadband spectrum of an active or starburst galaxy differs from that of a normal galaxy
- describe briefly the observed features of starburst galaxies and the four main classes of active galaxies (quasars, radio galaxies, Seyfert galaxies and blazars)
- understand the evidence that indicates the presence of a compact active galactic nucleus (AGN) in active galaxies
- explain why an AGN should emit broad lines, narrow forbidden lines and continuous radiation.
First Published: 09/08/2012
Updated: 12/09/2019
Rate and Review
Create an account to get more
Track your progress
Review and track your learning through your OpenLearn Profile.
Statement of Participation
On completion of a course you will earn a Statement of Participation.
Access all course activities
Take course quizzes and access all learning.
Review the course
When you have finished a course leave a review and tell others what you think.
It was hard to find text material that was at the right level. It was either much too advanced or too simple. This study material here, on the other hand, was stretching but manageable! I had read about Seyfert galaxies, quasars and radio galaxies, but I knew little about the differences between them and even less about how each might have originated.
Happily, while I certainly can't join all the dots in my head yet, I now have a much more integrated picture of how these things fit together. It is fascinating to consider (as the course does with evidence) that they might all be part of a kind of developmental continuum.
I must echo the previous contributors comment that one of the exercises (the main one in fact) is let down by a change in the format and layout of the NED (NASA/IPAC) database to which students are directed. While it was still possible to achieve most of the goals in the exercise, it was not straightforward.
It's also been a long time since I undertook the kind of calculations and equation manipulation that the course requires (I am a degree level engineer) so there was a lot of head scratching and more than a few arithmetic errors on the way!
Still, it has been rewarding and enriching. If you can jump over the 'math hurdle', I thoroughly recommend it!