fiber number issues

[I was on vacation for a few days.]

Just before I left, Melissa Ness discovered that instrumental fiber number is a good predictor of whether or not two stars will get similar abundances in APOGEE, either with The Cannon or with the standard pipeline! This is perhaps not a surprise: The different fibers have different line-spread functions, and sit on different parts of the detector. We discussed how to mitigate this, and looked at the dependence of the issues on fiber number and line-spread function FWHM separately.

For the nth time, I re-wrote my abstract (that is, the scope of a possible paper) on what you could learn about a star's intrinsic properties from a Gaia-like parallax measurement. I think the focus perhaps should be the subjectivity of it: What you can learn depends on what you know and believe.

Hans-Walter Rix decided that my talk at the end of this week should be on the graphical model as a tool for data analysis. I hope he is right!