Goddard Space Flight Center, Greenbelt, Maryland 20771

ENGINEERING COLLOQUIUM and SCIENTIFIC COLLOQUIUM
John Bahcall Memorial Lecture

Monday, December 11, 2006 / 3:30 PM, Building 3 Auditorium

Richard Ellis

"Cosmic Dawn: The Quest to Find the Earliest Galaxies"

ABSTRACT -- Locating and characterizing the properties of the earliest galaxies represents the final frontier in our understanding of cosmic history. Most likely the first systems were low mass objects which merged to form the larger galaxies we see at redshifts 5-6. Their abundance and star formation rates may have been sufficient to reionize the Universe bringing the `Dark Ages' to a close. The lecture will describe the observational challenges we face in locating this population with present facilities, the progress made so far, and the importance of continuing this quest in preparation for more detailed studies with the James Webb Space Telescope.

SPEAKER -- Richard Ellis is the Steele Professor of Astronomy at Caltech and has published extensively in the fields of observational cosmology, large scale structure and the evolution of galaxies. A regular Hubble user, he has consistently demonstrated the benefits of linking space-based data with ground-based spectroscopy. A Welshman by birth, Richard initiated the now well-established cosmology group at Durham before becoming the Director of the Institute in Astronomy at Cambridge. He moved to Caltech in 1999 and plays a leading role in that institute's plans for access to a new large ground-based telescope.