Wednesday, July 15, 2009

Results! (sort of)

Well this week I've actually accomplished several things.
I sent out a paper to several of Beth's collaborators detailing my results for the kurtosis of the various dwarf galaxies' velocity distributions.
For the most part, their small star numbers mean that their negative kurtosis falls in line with the simulated results for a normal distribution with the same number of stars.

However, Canes Venatici II has a random statistically significant high kurtosis, which is probably due to its having several far off outliers (making thicker tails, which result in higher kurtosis, remember?).
But for the rest of them we'll need more stars to determine anything else through that method.

But I also decided that there is almost definitely some rotation going on in Willman I. I plotted the systematic velocities in various sectors of the data, which seem to show that the "left" side is moving towards us faster than the average velocity, and the "right" side is relatively moving away from us. When I chopped out the stars with high metallicity, the probable outliers, I saw a really apparent gradient in the systematic velocity distribution. It's pretty neat!

It's probably evidence for streaming motions, although I'm still not entirely sure what that means, other than the fact that it is a result of tidal disruption.

To Do:
1) Beautify my kurtosis/skewness plots per Josh's suggestion.
2) Figure out what's going on with Nmix/correspond with Jay.
3) Look for rotation in the other galaxies.
4) Take a nap! The midnight Harry Potter viewing was probably not the brightest idea, despite being unexpectedly funny and entertaining.

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