2018-08-19

dynamics, abundances, and a likelihood function

In an undisclosed location off the grid I worked on my code to leverage element-abundance invariances of stars (in the GALAH Survey) to deliver dynamical invariants. I switched from a non-parametric abundance model that put the stars into abundance bins to a parametric model which makes the abundances a smooth function of actions. I also improved my action-computing code and built an interpolator to speed things up. And suddenly my likelihood function got really smooth, and it peaks at sensible dynamical parameters for the Milky Way disk! So I have a project. Note that the way I am operating is to work on the likelihood function until I can see that it behaves sensibly on slices (lines in parameter space) and only then will I think about the inference more generally.

After that success, I tweaked code, ran stuff, and started making an outline of the hard parts of the paper I need to write.

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