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Physics and Astronomy

Physics & Astronomy Colloquium

3:30 PM, Friday, September 5th, 2014
Room 155, Chem-Phys Building

Dr. Heidi Newberg
Rensselaer Polytechnic Institute


Your textbook is still wrong about the Milky Way galaxy

Fifteen years ago, we modeled the distribution of stars in the Milky Way using three components: an exponential disk, a power law spheroid, and a bulge. Then, we discovered the distribution of stars in the spheroid was lumpy due to the accretion and tidal disruption of dwarf galaxies that ventured too close the the Galactic center. We now wonder whether the Milky Way has a classical bulge at all; likely the bulge-like feature we see is instead due to the Galactic bar. And most recently, we are discovering large scale departures from the standard exponential disk. New discoveries point to variations in the expected bulk velocities of stars in the Galactic disk, and oscillations in the spatial densities of disk stars. Some believe these observations point to a wave response to the passing of dwarf galaxies (or dark matter lumps) through the Milky Way's disk. These waves may also explain the observed rings of stars, 15-25 kpc from the Galactic center, which is farther out than we originally believed the disk to extend.

Refreshments will be served in CP 179 at 3:15 PM