University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Thursday, December 6th 2018
3:35 pm:
Speaker: Stacy McGaugh, Case Western
Subject: Dynamical Regularities in Galaxies and their Implications for Dark Matter
Refreshments in atrium after the Colloquium.

The flat rotation curves of galaxies were a surprising observation that helped establish the dark matter paradigm. Flat rotation curves are only the first of a series of striking regularities in the dynamics of galaxies. The amplitude of the flat rotation speed is not random; it correlates strongly with the mass observed in stars and gas (the baryonic Tully-Fisher relation). At the centers of galaxies, the dynamical surface density correlates with the observed surface brightness of stars (the central density relation). At all observed radii, the observed centripetal acceleration correlates with the acceleration predicted by the observed distribution of baryons (the radial acceleration relation). These empirical relations inform our thinking about the missing mass problem in ways that were not available when the current paradigm was established.

Faculty Host: J. Woods Halley

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