RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 24 May 2018, 11:00-12:00; Duffield Lecture Theatre

Richard Ellis

"Early Galaxies and Cosmic Reionization: Progress and Challenges"

The birth of galaxies represents the last unexplored frontier of cosmic history and it is commonly believed such early systems led to the transformation of neutral gas in the intergalactic medium into its presentfully-ionized state. Some progress has been made in charting the demographics of early galaxies into the era when reionization is thought to occur, but little is known about their nature of their stellar populations, the possible role of active nuclei and whether galaxies are capable of generating sufficient ionizing radiation. Spectroscopy holds the key to addressing these questions, targeting both individual sources at high redshiftas well as carefully-chosen analogs at intermediate redshift. I will describe the recent progress and challenges as we anticipate the launch of JWST and the arrival of next-generation large telescopes.