generative models for quasars

I spent part of the day working with Christina Eilers on her Gaussian process latent-variable model for quasar spectra and physical properties. We re-wrote our title and abstract and went through the math in the paper. It's time to finish this up! We find that we can predict quasar masses with good accuracy (based on held-out data) based on single-epoch, limited-coverage optical spectra. It's sweet. And Eilers has beautiful demonstrations that she can predict unobserved spectral regions, because the model is trained on different quasars at different redshifts with different data. The big problem with this model is that it scales poorly; we can't imagine training on thousands of objects without substantial engineering efforts (and maybe not ever).