Shells in Space

Speaker: Dr Cullan Howlett
Affiliation: University of Queensland

Abstract

Galaxies in the Universe are not found randomly. Instead, they sit within a vast pattern we call the 'cosmic web'. In this talk I'll provide a general overview of how we are mapping this web using millions of other galaxies and using these maps to understand the nature of gravity and the role it has played in our Universe's formation and evolution. I'll then dive into detailing one particularly striking feature we see spread throughout the cosmos --- the remnants of enormous shells of galaxies and dark matter left over since the Big Bang. These so-called 'Baryon Acoustic Oscillations' provide some of the best probes of our cosmological model. Evidence will be presented for their existence, including my recent work on the detection of the first individual and almost complete example. Finally, I'll end with a discussion of imminent results from the Dark Energy Spectroscopic Instrument showing how we are using these shells to provide the tightest constraints on the properties of our Universe to date.