Dark Matter in the Milky Way
Although our every day world is composed almost entirely of atoms and
molecules, the universe that surrounds is mostly invisible. It is
composed of about 4 per cent baryons (regular matter), 76 per cent
dark energy, the repulsive force that accelerates galaxies away from
each other, and 20 per cent dark matter, which keeps galaxies
together. Presently, the best candidate for dark matter is weakly
interacting massive particles. Millions upon millions of these
particles zip right through our bodies every second, but because they
interact so weakly, we never even notice.
Scientists around the world have been trying to
detect these particles with massive detectors, as well as through
indirect methods with astrophysical observations. However, to
place limits on how often these particles interact with baryonic
matter as well as each other, we need to know how the dark matter is
distributed throughout the galaxy.
With Avi Loeb, I ran simulations of galaxy
mergers and formation to understand the effect the baryonic components
of galaxies (i.e. stars and gas) have on the distribution of dark
matter in the inner regions of galaxies, where we expect the dark
matter to annihilate itself. In my thesis, I discuss the
distribution of the dark matter in the Milky Way and how the baryons
can kick out the dark matter to the outer reaches of the galaxy,
making the dark matter even more difficult to detect.