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.