Quasars are among the most distant and most luminous objects in the universe. There are still many unanswered questions about these ob ects. Dr. Impey and his collaborators are studying several basic j aspects of quasars: (1) The mechanism that produces strong radio emission in a subset of the quasars and not in others - how is this mechanism related to that which produces the eniission at other wavelengths? (2) The nature of the evolution of the number density of quasars with cosmic time - at what epoch did the first quasars form? (3) the observable properties of the quasar and their relationship to the morphology and environment of the quasar host galaxies, (4) The nature of the quasar broad-baseline spectral energy distributions - what thermal and non-thcrmal emission mechanisms are at play? This research is a continuation of more than a decade's work on such problems, much of which was devoted to the design, execution, and exploitation of the largest survey for quasars completed to date, the Large Bright Quasar Survey (LBQS). Dr. Impey is completing two additional surveys: (1) The FIRST (Faint Images of the Radio Sky at Twenty-one centimeters) survey which is complimentary to the LBQS, and (2) a new multicolor survey covering 1000 square degrees targeting quasars within a half billion years after the big bang.
