Sunday, March 30, 2008

Um, Active Galactic Nuclei?

Group 1 were off to a tricky start on day 2 of their University of Southampton and University of Tenerife collaborative Astrophysics ┬┤Design a Gamma Ray Telescope' project when Babel Fish translated 'initial idea' as 'tapeworm' from Spanish. Working in two languages can be a difficult business, especially when your Spanish phrase book doesn't contain the words 'Active Galactic Nuclei'.

An active galactic neucleus (AGN) is a region at the centre of a galaxy which radiates energy in many wavelengths throughout the electromagnetic spectrum.

The nucleus gives off high energy radiation like gamma-rays and the further away that you get from the nucleus the lower the energy given off eg. radio waves and infrared, visible, and ultraviolet light. A galaxy hosting an AGN is called an active galaxy. The radiation from AGN is believed to be a result of accretion on to a super massive black hole at the centre of the galaxy. AGN are the most luminous persistent sources of electromagnetic radiation in the universe, and as such can be used as a means of discovering distant objects; their evolution as a function of cosmic time also provides constraints on cosmological models.

There are lots of different types of AGN that can be observed with different electromagnetic emission characteristics. The reason that there is a difference is because of the positioning of the earth in comparison to the AGN. Jets of material are emitted from AGNs and we might observe the jets as they emit material towards earth - or we may see the jets from the side.

Group 1 are trying to design a telescope to observe AGN around the galactic plane.


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