interstellar medium

In transit to Paris, I worked on a problem given to me by Rix and Brent Groves (MPIA): Model the dust emission in M31 at the resolution of the highest-resolution Herschel maps, but constrained by all the maps. This is a perfect job for the Tractor but it requires creating new objects (think unresolved, emitting dust blobs). I didn't get very far, because it is a substantial generalization of what we have. What we have doesn't currently constrain the spectral energy distribution of any source very much a priori. That is, the Tractor doesn't yet have strong priors on emission mechanisms.