## Monday, May 21, 2012

### Links for the week: 20th May

I meant to put this out yesterday, but the supernova post took a bit longer to write than I was hoping. Anyway, here's a list of interesting links.

Physics links:
• Last week I linked to a paper by Moni Bidin, Carraro, Mendez and Smith that claimed to have detected no evidence for dark matter affecting the kinematics of stars in the solar neighbourhood. I mentioned that this was not without controversy, and indeed this morning there was a new preprint by Bovy and Tremaine on the arXiv, who claim the Moni Bidin et al result is due to a key assumption that is not supported by the data. I haven't had time to read the paper yet, so I'll just quote from the abstract:
"We show that this result is incorrect and that it arises from the invalid assumption that the mean azimuthal velocity of the stellar tracers is independent of Galactocentric radius at all heights; the correct assumption -- that is, the one supported by data -- is that the circular speed is independent of radius in the mid-plane."
• Suppose you have three upturned cups, and you are 90% certain that there is a ball under one of them. You turn two of them over and find no ball — how confident are you that the ball is under the third cup? Philip Gibbs gives a nice little argument illustrating Bayes' theorem, and uses it to argue that we shouldn't give up on SUSY yet.

Other links: