Monday, 22 September 2008

S282: TMA-4

Its the last of the TMAs for this course. This is probably one of the more scary ones, as I found the first book much easier to digest in terms of concepts and ideas than book 2. Anyway, onwards...

It starts, conventionally enough, with question 1.
This consists of an image of a galaxy, and a spectral diagram of the same, and then there are a variety of questions on it. Firstly, just from the image you are asked to work out if you think this is a regular or active galaxy. Also what galaxy classification would you give to it?
Then there is a collection of data which has to be plotted as a graph to give the spectral signature of the galaxy. Again you have to discuss whether this looks like data from a normal or active galaxy.
The next part asks you to pick between a radio-loud and radio-quiet active galaxy, so rather giving the game away!
Next you have to make some more connections about a small part of the spectrum which is given to you as a graph. Looking at broadening of spectral lines and so on to work out what each shows.
Then some calculations on the broadening values to try and determine velocities.
Finally all the information has to be put together to determine what classification this galaxy is.

Question two is all about cosmology, and FRW models. It starts by getting you to define some FRW assumptions, then to imagine a universe with some given properties, and sketch out how the scale factor would change with time.
Then some algebra and stuff to work out if the curvature of space in this universe is negative.
A couple more calculations of other quantities such as the deceleration parameter and so on.
Then the last part throws in another observation and gets you to refine the model in the light of this new data.

Question 3 is only 5% and just asks you how you plan to revise for the exam. Not really any wrong answers here, although according to the tutor some interesting ideas are forthcoming!

This was a ratehr tough one for me, as cosmology is probably the weaker subject for me, and there hasn't been a lot of time for it to bed down in my mind. Still - its done now. I have a CMA to practice on - which is marked but not assessed, and then its just the exam left.

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