CAREER: Probing the High-Redshift Universe with Quasar Element Abundances

AST-9984040哈曼类星体（或类星体）是可观测宇宙边缘的明亮信标。 我们今天测量到的来自这些天体中最遥远的天体的光是在宇宙大约是现在年龄的17%时发出的，大约是10亿到20亿年。 光谱研究表明，即使在这些早期的类星体也含有重元素（或“金属”），推测是由本地恒星合成的。该项目是一个为期五年的计划，利用类星体元素丰度作为早期宇宙学时期星星形成和星系演化的示踪剂。从丰度推断的浓缩时间尺度和物理条件（如年龄、引力结合能，也许还有恒星形成环境的总质量）也应该有助于约束宇宙学本身的模型。早期星星形成和星系演化是当今天文学中最活跃的研究课题之一。该计划对类星体附近丰度的强调将为其他探索更广泛结构或使用非常不同的数据和分析技术的研究提供重要补充。这些结果将特别有价值，因为它们对银河系核演化具有独特的限制。研究表明，从类星体光谱中的本征发射线和吸收线可以得到可靠的丰度和重要的恒星形成性质。这一方案将通过以下方式检验和扩展这些结果：1）包括更大的类星体数据样本-重点是最早的年代; 2）开发和比较更独立的丰度诊断; 3）专门针对相对铁丰度，以限制富集时间尺度; 4）将类星体结果直接与高红移星星形成和星系演化的其他研究进行比较。同样的数据和分析也必然涉及到与类星体本身有关的各种问题。 调查的结果将使人们能够解决基本问题，如类星体的形成和演变，以及它们的环境的起源、位置、动态和物理性质。该方案的一个组成部分是一个长期的教育和公众宣传计划。该计划包括1）将科学带给K-12学生和公众的战略，2）为本科生提供新的互动和“动手”计划，以及3）为研究生提供指导计划，为他们提供一系列职业选择，包括教育，工业和学术研究。 目标是为研究生课程设计项目，以提高他们在“实际”应用、团队管理、沟通和组织方面的技能。将安排与行业代表的会议，学生将被派往当地的行业中心，行业代表将被邀请参观天文系。 每周一系列的期刊俱乐部会谈（为学生和教师）将组织和研究生将走到当地的K-12学校参加一个公共宣传计划。这项推广计划将有利于K-12学生，激发他们对科学的热情，并让研究生成为积极的榜样。本科教育计划包括创新的课堂技术，如“概念测试”，接触当前的研究作为正常课程的一部分，并为有动力的大三和大四学生提供暑期研究项目。天文科学部为该项目提供支持。*

AST-9984040HAMANNQuasars (or QSOs) are bright beacons at the fringes of the observable universe. The light we measure today from the most distant of these objects was emitted when the universe was about 17% of its present age - roughly 1-2 billion years old. Spectroscopic studies show that even at these early times quasars contain heavy elements (or "metals"'), presumably a synthesized by local stars. This project is a five-year program to use quasar elemental abundances as tracers of star formation and galaxy evolution at early cosmological epochs. The enrichment time scales and physical conditions inferred from the abundances (such as the ages, gravitational binding energies, and perhaps total masses of the star-forming environments) should also help constrain models of the cosmology itself. Early-epoch star formation and galaxy evolution are among the most active research topics in astronomy today. This program's emphasis on the abundances near QSOs will provide a vital complement to other studies that probe more extended structures or use very different data and analysis techniques. The results will be particularly valuable for their unique constraints on galactic nuclear evolution. It has been shown that reliable abundances and important star-formation properties can be derived from the intrinsic emission and absorption lines in quasar spectra. This program will test and expand upon those results by 1) including larger QSO data samples - with an emphasis on the earliest epochs, 2) developing and comparing more independent abundance diagnostics, 3) targeting specifically the relative iron abundances to constrain the enrichment time scales, and 4) comparing the QSO results directly to other studies of high-redshift star formation and galaxy evolution. The same data and analyses will also necessarily address a variety of problems concerning the QSOs themselves. The results of the investigations will allow one to address fundamental issues, such as the formation and evolution of QSOs, and the origin, location, dynamics and physical nature of their environments.An integral part of the program is a long-range plan for education and public outreach. This plan includes 1) strategies for bringing science to K-12 students and the general public, 2) new interactive and "hands-on"' programs for undergraduates, and 3) a mentoring plan for graduate students that will prepare them for a range of career options, including education, industry and academic research. The goal is to design projects for graduate student classes that will enhance their skills in "practical" applications, team management, communication and organization. Meetings with industry representatives will be arranged and the students will be sent out to local industry centers and industry representatives will be invited to visit the astronomy department. A weekly series of journal club talks (for students and faculty) will be organized and the graduate students will go out into local K--12 schools to participate in a program of public outreach. This outreach program will benefit the K-12 students by stirring their enthusiasm for science and by having the graduate students be examples of positive role models. The undergraduate education plan includes innovative classroom techniques such as "concept testing," exposure to current research as part of the normal curriculum, and summer research projects for motivated juniors and seniors.The Division of Astronomical Sciences provides support for this project.***