Dartmouth Events

Abstract: Despite tremendous progress in cosmology over the last few decades, the nature of dark matter in our universe remains elusive. In this talk I will describe how the cosmic-dawn era, which saw the formation of the first galaxies, holds a wealth of information about the dark sector. The light from these first galaxies kickstarted the last major phase transition of our cosmos, as it went from cold and neutral to hot and ionized. This transition will soon be mapped by different telescopes, providing us with a powerful window to understand dark matter. I will present the first results from the 21-cm HERA instrument, and show their implications for both dark matter and the astrophysics of the first galaxies. I will also show how to utilize the Hubble and James Webb Space Telescopes to determine whether dark matter is cold, warm, or self interacting. This will push our knowledge of dark matter to smaller scales—and earlier times—than ever before.