Quasar Research

亚利桑那州大学的克雷格·福尔茨研究类星体是宇宙中最遥远、最明亮的天体之一。关于这些观察，仍有许多悬而未决的问题。Impey博士和他的合作者正在研究类星体的几个基本方面：(1)在一部分类星体中产生强射电发射而在其他类星体中不产生强射电发射的机制--这种机制与在其他波长产生否认的机制有何关系？(2)类星体数密度随宇宙时间演变的本质--第一类星体形成于什么时期？(3)类星体的可观测特性及其与类星体宿主星系的形态和环境的关系，(4)类星体宽基线光谱能量分布的本质--是什么热和非热发射机制在起作用？这项研究是对这类问题十多年工作的继续，其中大部分致力于设计、执行和开发迄今已完成的最大的类星体调查--大型明亮类星体调查(LBQS)。Impey博士正在完成另外两项调查：(1)第一项(21厘米处射电天空的微弱图像)调查，这是对LBQS的补充；(2)一项新的多色调查，覆盖了大爆炸后5亿年内的1000平方度的类星体。

AST 98-03072Christopher ImpeyCraig FoltzUniversity of ArizonaQuasar researchQuasars 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 jaspects 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.