Grant: Discovery Grants Program - Individual

Galaxies are islands of light and matter in a mostly-empty universe. The gravity of their dark matter holds together the gas and dust that make new stars and planets, recycling the heavy elements released at the end of stars' lives. Galaxies are found in a variety of shapes and sizes and in many different environments, including giant elliptical galaxies at the centres of galaxy clusters, medium-sized spirals like our own Milky Way found in galaxy groups, and ghostly `low surface brightness' galaxies found both in groups and in isolation. The goal of this research is to use observations of nearby galaxies to understand how galaxies change over time. Many physical processes are known to affect galaxy properties, including the gravitational effects of other galaxies; the radiation and matter emitted from stars, supernova explosions, and black holes; the gravity and motion of stars and gas within galaxies; and intergalactic magnetic fields. These processes work on time scales of millions or billions of years. We can't watch them happen, so the only way to understand these processes is through theoretical models tested against observations. Over the next five years, my research group will work to understand the history of star formation in nearby low surface brightness galaxies. Although they may make up the largest number of galaxies in the universe, these elusive objects are less understood than bright galaxies like our Milky Way. We want to understand whether they formed their stars all at once long ago, at a slow-but-steady rate over time, or in bursts of activity separated by long quiet periods, and how they are turning gas into stars now. This will be achieved by measuring properties of these galaxies' stars, star clusters, active supermassive black holes and interstellar gas. Studies of these galaxies will test whether conclusions about star formation gained from studies of bright galaxies are universally applicable. This research will combine observations from many different telescopes, including some of the newest and most advanced facilities available to Canadian astronomers. These observatories produce massive digital datasets, so using their data also requires massive amounts of computing power. In meeting this computational and statistical challenge, trainee researchers will develop technical skills that are transferable to many areas beyond astronomy. The measurements that we make will provide critical tests of and input to theoretical models of galaxy formation and evolution, ultimately improving our understanding of how the universe has changed over time to arrive at its present state.