I had a great conversation this morning with Yashar Hezaveh (Flatiron) about problems in gravitational lensing. The lensing map is in principle a linear thing (once you set the nonlinear lensing parameters) which means that it is possible to marginalize out the source plane analytically, in principle, or to apply interesting sparseness or compactness priors. We discussed computational data-analysis ideas.
Prior to that, I had an interesting conversation with Rodrigo Luger (Flatiron) and Dan Foreman-Mackey (Flatiron) about the priors we use when we do stellar-surface or exoplanet-surface modeling (map-making). Most priors that are easy to use enforce smoothness, but our maps might have sharp features (coastlines!). But we more-or-less agreed that more interesting priors are also less computationally tractable. Duh!
At mid-day, Chiara Mingarelli (Flatiron) argued in a great seminar that pulsar timing will make a detection in the next years. Her argument is conservative, so I am very optimistic about this.