Eilers

Christina Eilers (MIT) is in town for the week. We realized that we have four projects: Work on the kinematic signatures of spiral arms in the Milky Way disk; design a self-calibration program for stellar element abundances; create a latent-variable model (like The Cannon) for estimating black-hole masses from quasar spectra; infer simultaneously the large-scale structure towards luminous quasars and the quasar lifetimes using rest-frame ultraviolet spectra.

Because it is the most mature, our highest priority is the disk paper. We discussed the scope of this paper, which is: Good visualization of the velocity structure; a toy model to relate the velocity amplitude with the density amplitude of any dynamically-driven perturbation; rough measurement of the pitch angle; comparison to other claims of spiral structure in the neighborhood. We think we have the clearest view of the spiral structure, and the only truly dynamical measurement.