2018-10-17

bar, spiral structure, and interactions

Stars meeting at Flatiron was absolutely great today. Discussions by Cunningham (UCSC) who has done HST astrometry, Keck spectroscopy, and kinematic analyses of large samples of Milky Way halo stars. She is full stack! And by Brendan Brewer (Auckland) who is working on information theory (in a Bayesian context) to think about experimental design in realistic contexts. My loyal reader knows how close to my heart that is.

Also at Stars meeting, Pearson (Flatiron) and Laporte (UVic) showed models of the effects of the Sagittarius merger on the Milky Way disk. Because the disk is such a sensitive dynamical “antenna”, it should show evidence of this encounter. In the simulations, it appears that the encounter is capable of raising the bar and spiral structure that is very similar to what is observed. Like very similar. This is incredibly exciting: If this pans out, it opens up use of bars and spirals to find or time or weigh galaxy encounters and interactions. Maybe even with dark-matter substructures! Super exciting.

Before all that, Sinan Deger showed me nice results on galaxy morphologies as a function of environment and location around clusters, and Ari Pakman (Columbia) gave a beautiful math-filled talk about Hamiltonian Monte Carlo. He had a very nice, extremely simple proof and picture for why HMC works.

No comments:

Post a Comment