Quillen

I spent the day at Potsdam, to participate (and give a talk) in the Wempe Award ceremony; the prize went to Alice Quillen (Rochester), who has done dynamical theory on a huge range of scales and in a huge range of contexts. I spoke about how data-driven models of stars might make it possible to precisely test Quillen's predictions. After my talk I had a long session with Ivan Minchev (AIP), Christina Chiappini (AIP), and Friedrich Anders (AIP) about work on stellar chemical abundances in the disk. They are trying to understand whether the alpha-rich disk itself splits into multiple populations or is just one. We discussed the possibility that any explanation of the alpha-to-Fe vs Fe-to-H plot ought to make predictions for other galaxies. Right now theoretical expectations are soft, both because star formation is not right in the cosmological models, and because nucleosynthetic yields are not right in the chemical evolution models. We also discussed Anders's use of t-SNE for dimensionality reduction and how we might test its properties (the properties of t-SNE, that is).