Dwarf galaxies in deep-wide surveys: a new frontier in the study of galaxy evolution

Galaxies, like our own Milky Way, form the building blocks of the observable Universe. Our current statistical understanding of how galaxies form and evolve over time is overwhelmingly dominated by massive Milky Way-like galaxies. This is because massive galaxies are bright enough to be detectable in past large observational surveys, which underpin our understanding, across cosmic time. However, low mass ('dwarf') galaxies, although fainter than their massive counterparts, actually dominate the Universe by number, making them central to a complete understanding of galaxy evolution. However, dwarf galaxies are essentially missing from past large surveys because, given their low sensitivities, dwarfs are too faint to be detected in significant numbers outside the very nearby Universe. As a result our current understanding of our how the Universe evolves is biased and potentially highly incomplete.

However, new surveys, which not only offer large sky areas but also have sensitivities that are 100 times greater than past surveys are poised to revolutionise our understanding of galaxy evolution, by detecting, for the first time, millions of dwarf galaxies in the nearby Universe. In this programme we will use these new surveys to perform the first statistical observational studies of dwarf galaxies. We will then compare our observational findings to state-of-the-art computer simulations, which will enable us to understand the physical processes that drive the formation and evolution of dwarf galaxies over cosmic time.

Given the uncharted nature of this critical domain, these studies will significantly improve the current state-of-the-art in our understanding of galaxy evolution and lay the groundwork for further exploration of the dwarf regime by the international astronomical community using new and future surveys.