Astro 2020 Science White Paper Resolving Galaxy Formation at Cosmic Noon Thematic Area Galaxy Evolution
Cosmic noon was an active and critical period in the evolution of galaxies. During this epoch, roughly 10 Gyr ago, star formation and black hole accretion were at their highest rates. Key characteristics of today's galaxies, such as regularly rotating disks, bulges, and a population of dead galaxies, were just emerging. We describe opportunities over the next decade to transform our view of galaxy evolution at this important epoch by resolving both early galaxies and their surrounding gaseous media. High angular resolution spectroscopic observations are needed to resolve individual star forming regions, dissect emerging substructures such as disks, clumps, and bulges, map galaxy scale winds, and identify supermassive black holes. On larger scales, deep optical spectroscopy is needed to characterize and resolve the circumand intergalactic media within which galaxies are forming by using dense networks of faint background galaxies to probe gas in absorption. Only extremely large telescopes (ELTs) provide both of these capabilities, thereby delivering an unprecendented density of information over a wide range of scales, spanning 100 pc to 1 Mpc. Multi scale resolved observations will be essential to understand the flow of baryons through galaxies, the mechanics of feedback, and its role in shaping early galaxies' star formation and structural evolution.