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Your textbook is still wrong about the Milky Way galaxy

Date:
-
Location:
CP155
Speaker(s) / Presenter(s):
Heidi Newberg (RPI)

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