Two great seminars today. The first was by Ross Fadely (Haverford), who had done full brute-force modeling of strong gravitational lensing in a CDM-substructure context. He lays down CDM-compatible substructure in an enormous outer loop of realizations, and then does lens model selection within that loop. Brute force modeling that warms the heart. He finds, unfortunately, that the lenses don't obviously contradict CDM.
The second was by Josh Winn (MIT), who talked about very clever measurements of star-spin vs orbital angular momentum mis-alignment in exoplanet systems. The data show some beautiful regularities that are not implausibly explained by a combination of few-body effects driving inward migration (of hot Jupiters) followed by tidal damping of inclinations and eccentricities on pretty short time-scales. He argued, effectively (though not explicitly) that exoplanets measure the tidal dissipation timescales (or tidal quality factor) of convective stars much better than models can predict it. In the question period, the subject of free-floating planets came up. Mental note to self: Discover these!
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