from The Open University
Alternatively you can skip the navigation by pressing 'Enter'.
The Met: Policing London: Episode FiveFriday, 31st July 2015 00:50 - BBC TwoIn the final episode of OU/BBC's The Met a new recruit learns his way around the London streets and Homicide... Read more: The Met: Policing London: Episode Five
Life: PrimatesFriday, 31st July 2015 11:00 - Eden
A History of Ideas: Writer Lisa Appignanesi on the Love of ChildrenFriday, 31st July 2015 12:04 - BBC Radio 4
Life: PrimatesFriday, 31st July 2015 17:00 - Eden
The Met: Policing London: Episode FiveAvailable until Friday, 7th August 2015 01:50In the final episode of OU/BBC's The Met a new recruit learns his way around the London streets and Homicide... Read more: The Met: Policing London: Episode Five
A History of Ideas: Theologian Giles Fraser on AltruismAvailable until Wednesday, 27th July 2016 00:00
Great Ormond Street Hospital: Fix my genesAvailable until Friday, 28th August 2015 02:45
The Bank: LendingAvailable until Thursday, 27th August 2015 03:00
Can we find the rest of MH370?It looks as if part of MH370, the lost Malaysian Airlines jet, has been found. Will this help us... Read more: Can we find the rest of MH370?
Take the photographic memory testCan you capture scenes just by looking at them? Find out with our photographic memory test. Launch now: Take the photographic memory test
Beginners’ Italian: food and drinkThis free course, Beginners’ Italian: food and drink, focuses on buying drinks and snacks in an... Try: Beginners’ Italian: food and drink now
English: skills for learningThis course is for anybody who is thinking of studying for a university degree and would like to... Try: English: skills for learning now
Introduction to active galaxies
The field of active galaxies is recognised as one of increasing importance. But how do...
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 unit examines the different types of active galaxy and looks at the crucial role of the active galactic nucleus and the energy source at its heart.
By the end of this unit 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;
- give an account of an accreting massive black hole as the engine of the AGN and relate its luminosity to the mass accretion rate;
- outline some of the outstanding problems relating to the evolution of active galaxies.
- Current section: Introduction
- Learning outcomes
- 1 Overview
- 2 The spectra of galaxies
- 3 Types of active galaxies
- 4 The central engine
- 5 Models of active galaxies
- 6 Outstanding Issues
- 7 Unit Summary
Study this free course
Enrol to access the full course, get recognition for the skills you learn and track your progress. Make your learning visible!
Introduction to active galaxies
Active galaxies provide a prime example of high-energy processes operating in the Universe. This unit introduces the evidence for activity from the spectra of some galaxies, and the concept of a compact active galactic nucleus as a unifying model for the observed features of several types of active galaxy. It also develops the key skill of applying arithmetic and simple algebra to solving scientific problems.
This course is an adapted extract fromt he course
Copyright & revisions
Originally published: Monday, 16th May 2011
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements section.
- This site has Copy Reuse Tracking enabled - see our FAQs for more information.
If you enjoyed this, why not follow a feed to find out when we have new things like it? Choose an RSS feed from the list below. (Don't know what to do with RSS feeds?)
Remember, you can also make your own, personal feed by combining tags from around OpenLearn.