Lecture 4/4 : All Hope Abandon, Ye Who Enter Here
And so at last my first foray in lecturing draws to a close. This time I look at problems in galaxy evolution and how they might be solved. The missing satellite problem is just one aspect in the much greater missing galaxy problem. After nearly 20 years, simulations are finally getting the number of predicted galaxies to match the observations... but they're so complicated, this doesn't necessarily mean they've got the answer right. Planes of satellite galaxies, whilst generating papers with hundreds of citations, I show are just pure nonsense and absolutely nothing to worry about, but if they're real then they're not the dark matter killer they're claimed to be. Ultra diffuse galaxies, dark galaxies, the Tully-Fisher relation, the mass discrepancy acceleration relation, and a showdown between MOND and CDM : it's all in here.
Regular blog rants about Jeremy Corbyn and Plato can now resume unhindered. I know y'all dying for that. :P
Though I'll probably be extracting parts of this to make shorter, more outreachy posts for those who don't want to wade through everything here.
This post is a placeholder. I will add a better summary here in due course.
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Of course you can prove a negative. In one sense this can be the easiest thing in the world : your theory predicts something which doesn...
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In the last batch of simulations, we dropped a long gas stream into the gravitational potential of a cluster to see if it would get torn... -
And more importantly, how not to build a galaxy. Uniform discs of pure gas turn out to be almost impossible. Exponential discs - where ther...
I figure, over this little course of lectures, about 3/4 of what I thought I knew about this subject was either wrong or too simplistic.
ReplyDeleteThen my secret agenda has been achieved ! :)
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