Shedding Light on Dark Matter with Gravitational Lensing

Chuck Keeton, Rutgers

The standard paradigm for cosmology predicts that every massive galaxy should be surrounded by a myriad of "dark dwarfs" made entirely of dark matter. The abundance of dark matter substructure is sensitive to the nature of the dark matter particle. The gravitational deflection of light provides a unique opportunity to detect dark dwarfs and probe the physics of dark matter. The theory of gravitational lensing with stochastic substructure is rich and tractable, providing a firm foundation for observational studies. Existing data reveal the average amount of dark matter substructure in galaxies, and future large samples hold great promise for revealing even more about the exotic substance that permeates the universe.