Research project How the Universe was Reionized

The most recent of these transitions is known as cosmic reionization, during which the overwhelming majority of intergalactic matter (mostly hydrogen gas) was transformed from a cool, neutral state to a warm, ionized medium.  There is little doubt that this process was driven by ultraviolet radiation emitted by the first stars and black hole-related phenomena in proto-galactic structures.  However, understanding the nature of these objects, as well as how much energy they radiate into the early universe, remain tremendously challenging.

This KAW-funded project aims to take a multifaceted approach to cosmic reionization and the astrophysical objects that were responsible, using an array of modern telescopes.  For example:

• We are leading efforts to identify some of the first black-holes using the Hubble Space Telescope (HST).
• We participate in four HST Large Programs, one of which we lead, to study local ‘starburst galaxies’ (similar in their properties to those that reionized the universe)
• We are leading the ‘first galaxies’ aspects of the largest JWST campaign to be awarded during the first cycle of the observatory – the Parallel Application of Slitless Spectroscopy for Galaxy Evolution (PASSAGE).
• All the above is supported by any number of observational campaigns on the largest ground-based telescopes, lead both by group members and through international collaborations.