Abstract:
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 present fully-ionised state. Some progress has been made in charting the demographics of early galaxies into the era when reionisation is thought to occur, but little is known about the nature of their stellar populations, the possible role of active nuclei and whether galaxies are capable of generating sufficient ionising radiation. Spectroscopy holds the key to addressing these questions, targeting both individual sources at high redshift as well as carefully-chosen analogues at intermediate redshift. I will describe the recent progress and challenges as we anticipate the launch of the James Webb Space Telescope and the arrival of next-generation large telescopes.
Brief Bio:
Richard Ellis is Professor of Astrophysics at University College London. Professor Ellis obtained his Ph.D. at Oxford University in 1974.
As a young researcher he established a major astronomy group at Durham University and later became the Director of the Institute of Astronomy
at Cambridge University. He emigrated to the California Institute of Technology in 1999 where he was Director of the Palomar and Caltech Optical Observatories.
Ellis’ research interests span the distribution of dark matter, the history of the cosmic expansion and studies of the first galaxies seen when the Universe was
less than 5% of its present age. His awards include the Gruber Cosmology and Breakthrough Foundation Prizes and the Gold Medal of the Royal Astronomical Society.
He is a Fellow of the Royal Society and was awarded the title of Commander of the British Empire by Queen Elizabeth in 2008 for his contributions to international science.