How to Regulate Galaxy Growth Through Cosmic History

ABSTRACT: One of the most important realizations of the last fifteen years is the vital role that galactic feedback must play in the evolution of galaxies. An umbrella term for a wide array of physical processes that already began to affect galaxies in the first billion years after the Big Bang, feedback allows galaxies to self-regulate their growth, links the buildup of stellar mass and black holes, and connects galaxies to the dark matter haloes they live in. Because of the vast range of physical and temporal scales involved and a lack of direct observational tracers, studying feedback in action has remained difficult. I will discuss a few of my ongoing efforts to understand the causes and effects of galactic feedback, focusing on populations of galaxies that show the effects of feedback most strikingly. With the completion of ALMA we are now able to detect and resolve galaxy-scale cold gas outflows in decent-size samples of starbursts, quasars, and soon even 'normal' galaxies at z = 4 - 7, an era that saw the cosmic star formation rate skyrocket as galaxies grew and evolved. While a complete statistical understanding of feedback and galactic outflows will require the powerful observatories of the next decades, I will argue that significant progress can be made now by carefully picking and choosing galaxies where the effects of feedback are most prominent.