Today Coryn Bailer-Jones (MPIA) gave a great talk at MPIA about the upcoming first data release from the Gaia mission. It will be called “Gaia DR-1” and it will contain a primary release of the TGAS sample of about 2 million stars with proper motions and parallaxes, and a secondary release of about a billion stars with just positions. He walked us through why the DR-1 data will be very limited relative to later releases. But (as my loyal reader knows) I am stoked! The talk was clear and complete, and gives us all lots to think about.
In the morning, Hans-Walter Rix and I met with Karin Lind (MPIA), Maria Bergemann (MPIA), Sven Buder (MPIA), Morgan Fouesneau (MPIA), and Joachim Bestenlehner (MPIA) to talk about how we combine Gaia parallaxes with optical and infrared spectroscopy to determine stellar parameters. The meeting was inspired by inconsistencies between how we expected people to use the spectral and astrometric data. We learned in the meeting that there are simple ways forward to improve both the spectral analysis and things that will be done with Gaia. I showed the crowd my probabilistic graphical model (directed acyclic graph) and we used it to guide the discussion. Almost as useful as showing the PGM for the full problem was showing the PGMs for what is being done now. As my loyal reader knows, I think PGMs are great for communicating about problem structure, and planning code.