Alan Duffy (University of Melbourne)

Alan Duffy Colloquium: First Galaxies and DRAGONS

Marsfield

Abstract

Title: First Galaxies and DRAGONS

Abstract: One of the most important questions in astronomy today is the source of the ionising photons that caused a predominantly neutral Early Universe to evolve into the ionised one we see today. I have investigated this Epoch of Reionisation with a a new suite of high resolution hydrodynamical simulations, created within the DRAGONS group. These simulations show that the galaxies observed at early times represent merely the tip of an iceberg; with a hidden population of faint galaxies that can Reionise the Universe with ease. Paradoxically although the global star formation history of the early universe is strongly constrained by current observations, we actually know little about the nature of star formation at this time (as given by the specific star formation rate). I will demonstrate that we can understand these objects but need to push our observations deeper, a goal that will likely have to await the James Webb Space Telescope.