Our current picture of the birth of the universe is that it began with the Big Bang and has since expanded to the present day. In the 13.8 billion years between then and the present day, the first galaxies assembled, grew, and large scale structures and galaxy clusters condensed, and our own Milky Way was formed. The extragalactic group studies many aspects of this process from the first objects to light up in the universe, to large evolved galaxies in the cosmic backyard. Their approaches are largely observational, using data from major flagship telescopes on the ground and in space, as well as leveraging data from advanced computer simulations. Combning various approaches, they study
populations of stars and gas, and the interplay between the two, at all cosmic epochs over a wide range of physical scales.