information theory and stellar spectroscopy

[I am supposed to still be on vacation but we came back a day early.]

At the end of the day, Rix and I met with Yuan-Sen Ting (Harvard) and Ness to discuss the state of projects. Ting is modeling stellar spectra with linear combinations of model derivatives and has some extremely promising results (and some small bugs). We worked on diagnosis. One great thing about his project is that many of the results (on fake data, anyway) can be predicted exactly by methods of information theory. That is, he is close to having a testing framework for his scientific project! This relates to things CampHogg has discussed previously.

With Ness we went through all of the figures and discussed their relevance and necessity for her paper on measuring stellar masses and ages with The Cannon. Her current figures follow a very nice set of conventions, in which a progressive "grey" color map is used to indicate density (of, say, points in a scatter plot) but a sequential colored color map is used to indicate any other quantity (for example, mean stellar age in that location). The paper shows clearly that we can measure stellar masses and ages, and explains how. We made many small change requests.