Grant: Canada Excellence Research Chairs

The Universe is not static but continuously changing, even on human-observable timescales. Stars die in supernova explosions, black holes are fed by the gas around them, and neutron stars crash into each other. Transient astrophysics, also called time-domain astronomy, is the study of how astronomical objects change with time. Compared with a static view of the Universe, it provides a new dimension for understanding the grand story of how galaxies, stars, planets, and eventually life are formed. Transient astrophysics is driven by discovery. We aim to uncover new astrophysical phenomena and objects that challenge existing theory, lead to new hypotheses, and provide novel scientific applications. A recent outstanding example is the discovery of `fast radio bursts'. These radio flashes come from billions of lightyears away in distant galaxies. Their origins are one of the biggest mysteries in astrophysics. We aim to decipher the nature of fast radio bursts, and to use them to reveal the otherwise invisible gas between stars and galaxies. Fast radio bursts encode the history of their journey to Earth; they probe the intervening gas, the fuel for new stars, in unique and powerful ways. This will show us how stars and galaxies evolve over cosmic time. We also aim to explore the skies as never done before, to search for novel astrophysical phenomena that give insight into the Universe's extremes. To achieve this, we need to construct ground-breaking radio telescopes that can continuously scan wide swaths of the sky, identify ephemeral signals in real-time, and pin-point the source's position with exquisite precision. This is challenging because the scientifically interesting astronomical signals constitute only one millionth of the torrent of data streaming through the telescope. We will greatly expand the Canadian CHIME telescope, creating a network of radio antennas that spans the continent and discovers dozens of precisely localised fast radio bursts per day. Each of these signals provides a view of the Universe's structure in one direction. Combined, the thousands of fast radio bursts that we will discover and localise will give an unprecedented 3-D map of the Universe. The fast radio burst phenomenon came as a huge surprise, but we now know that we are only seeing the tip of the iceberg of a much larger population of astronomical signals that can transform our understanding of astrophysics and cosmology. We will capitalise on this opportunity.