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- An overview of active galaxies
An overview of active galaxies

Active galaxies provide a prime example of high energy processes operating in the Universe. This free course gives an overview of active galaxies, including the supermassive black holes that power the engines at their centres, and the emission processes by which we detect and study them. It also gives practice in mathematical techniques for analysing data and theoretical models.
Course learning outcomes
After studying this course, you should be able to:
- recognise the terminology which is used to describe the properties and behaviour of active galactic nuclei (AGN)
- manipulate numbers, algebraic symbols and mathematical functions in equations.
First Published: 09/08/2012
Updated: 17/10/2018
You can start this course right now without signing-up. Click on any of the course content sections below to start at any point in this course.
If you want to be able to track your progress, earn a free Statement of Participation, and access all course quizzes and activities, sign-up.
Course content
- Introduction
- Learning outcomes
- 1 Meet your first active galactic nuclei
- 2 Black holes: a reminder
- 3 AGN reside at the centres of galaxies
- 4 Black holes at the centres of ordinary galaxies
- 5 Distances in extragalactic astronomy
- 6 The key questions
- 7 Continuum emission processes
- 7 Continuum emission processes
- 7.1 Blackbody radiation
- 7.2 Free-free radiation
- 7.3 Polarization of electromagnetic radiation
- 7.4 Faraday depolarization
- 7.5 Emission from spiralling electrons: synchrotron radiation
- 7.6 Producing synchroton radiation in a laboratory
- 7.7 Radiation detection
- 7.8 Example 2 and questions
- 7.9 Compton scattering
- 8 Basic properties and historical perspective
- 8 Basic properties and historical perspective
- 8.1 Continuum spectra
- 8.2 Extended radio sources
- 8.3 Line spectra: ions and spectral lines
- 8.4 Line spectra: line flux and equivalent width
- 8.5 Line spectra: Activity 7 Colours and broad lines
- 8.6 Line spectra: Activity 8 Quasar redshifts
- 8.7 Luminosity functions
- 9 Conclusion
- Acknowledgements
preface of Peterson File
Article by A. Eckart and R. Genzel ‘Stellar proper motions in the central 0.1pc of the Galaxy’ File
Section 1.3 of B. M. Peterson An introduction to active galactiv nuclei File
Peterson Figures 1.1 and 1.2 File
Peterson Section 1.3.2 File
Peterson Sections 1.3.3 and 1.3.4 File
Peterson section 1.3.5 (pages 16 and 17) File
Peterson section 1.4 File
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15 hours study
Level 3: Advanced
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