Eastbourne, East Sussex BN20 9HT
Let There Be Light: Searching for the First Galaxies
Professor Richard S. Ellis (European Southern Observatory and University College London)
The first billion years after the Big Bang can be regarded as the final observational frontier in assembling a coherent picture of cosmic history. During this period early stars and galaxies formed and the Universe became bathed in ultraviolet light for the first time. Sometime during this era hydrogen in the intergalactic medium also transitioned from a neutral gas to one that was fully ionized. How and when did this `cosmic reionization’ occur and were early star-forming galaxies the primary agents? Recent measurements by the Planck satellite suggest that reionization was a rapid process that occurred later than originally thought. This development raises the exciting prospect that we may be able to directly observe the first galaxies. Deep exposures with the Hubble Space Telescope have provided the primary evidence that star-forming galaxies were present during the relevant period. Detailed spectroscopy of these galaxies is now required to address these important questions. I will review the rapid progress being made in this area with current large telescopes and the prospects with upcoming ones, including the James Webb Space Telescope and extremely large ground-based telescopes now under construction.
Biography: Richard Ellis studied at London and Oxford Universities and served as a professor and department head at Durham and Cambridge Universities. He moved to California in 1999 to assist in developing the Thirty Meter Telescope and was Director, Caltech Optical Observatories, with responsibility for the Palomar and Keck Observatories from 2000 to 2006. He returned to University College London in 2015 and is currently on leave as Senior Scientist at the European Southern Observatory in Munich.
Ellis’ research interests include the nature and distribution of dark matter, the history of the cosmic expansion and studies of the first galaxies seen when the Universe was less than 5 per cent of its present age. He is a Fellow of the Royal Society and a Commander of the British Empire. His awards include the Gruber Prize in Cosmology, the Gold Medal of the Royal Astronomical Society and the Breakthrough Foundation Prize in Fundamental Physics.