modeling images of galaxies

On Sunday, Lang came into NYC and we discussed his projects involving imaging data pipelines and the photometry and deblending of galaxies. Lang would like to make deblending a probabilistic operation, but this requires (in our outlook) a generative model of a galaxy image—a model that is good at the pixel level! This doesn't exist; exponential and de Vaucouleurs models are not good fits to the data in any sense of that term. There are shapelets and sechlets, but these (on the other hand) are pixel level with too much freedom. So we came up with the simplest possible model: other galaxies. Can we find a small number of galaxies that act as archetypes to fit other galaxies, and then use those for probabilistic deblending? We shall see.