My primary research interests are directed toward understanding when and how galaxies formed. To this end I have studied the structure, kinematics, and stellar populations of nearby elliptical and SO galaxies with the goal of inferring how they were built up in the distant past ("galaxy archeology"). When HST (the Hubble Space Telescope) was launched and the Keck 10-meter telescopes became available, we could directly look at the buildup of galaxies at early times in the life of the universe (using the astronomer's "time machines"). I was deputy Principal Investigator on the Advanced Camera for HST that was launched in 2002 and put onto Hubble by the astronauts during their last, wonderfully successful repair mission to Hubble. This camera has brought us remarkable views of the universe. By using this camera, along with an excellent group of collaborators and postdocs and students, we have been able to view directly galaxies within the first billion years of the Big Bang - looking back in time over 12 billion years. In two recent papers led by postdoc Bouwens the first detections and good limits were placed on galaxies at redshifts 7-10, or looking back over 13 billion years to within 400-600 million years of the Big Bang.
The new 8-10 meter ground-based telescopes like Keck, and HST and other space telescopes like Chandra and Spitzer, are helping astronomers learn much more about how galaxies develop. However, astronomers will probably only be able to study them during their birth throes with even more powerful telescopes. I am therefore particularly interested in the next generation of large ground and space telescopes for use in the visible, infrared and submillimeter spectral regions. I worked back in the late 1980s and early 1990s to develop the concept for an 8-m diameter cooled infrared space telescope (the Next Generation Space Telescope NGST - now called the James Webb Space Telescope JWST). I have been working with other scientists and technologists to develop space telescopes that are larger and even more powerful than HST. And looks forward to the time when the new Atacama Large Millimeter Array ALMA comes on line, and a new generation of 30-meter class telescopes become operational on the ground (the Thirty Meter Telescope TMT). The potential of a new class of telescope to observe planets directly around nearby stars (the Terrestrial Planet Finder Coronagraph TPF-C) is very exciting. The technology involved is very challenging but planet searches will be one of the exciting areas of the future and he is beginning his involvement in this exciting activity.
I have also been the chair of the Astronomy and Astrophysics Advisory Committee (AAAC). This committee offers advice to Congress and NSF, NASA and DOE on the implementation of the science program developed by the astronomy science community through studies carried out by the National Academy of Sciences.