Mykytyn and Patel got a full Gaussian Process code for fitting quasar lightcurves together and working today. Not bad for a day's work. And (thanks to a genius insight from Foreman-Mackey) we have a model for multiple-band quasar data, so that we can model any bands or any combination of multiple bands, whether the different bands are taken simultaneously (as with SDSS) or with large time lags between them (as with PanSTARRS). We will implement the multi-bandiness next week, but I am still pretty damned impressed with the full construction of a GP system from scratch and working on real data in one day.
In the afternoon, Arjen van der Wel (MPIA) gave a very nice talk about star-forming galaxies over cosmic time. He can show, explicitly in the data by fitting the distribution of galaxy shapes, that most of the stars in the Universe do indeed form in disks. That's a fundamental result. He also has interesting results on the mean properties of disk growth by star formation.