NSF Young Investigator: The Evolution of Normal Galaxies

在接下来的几年里，许多相互关联的项目将被进行，这些项目将解决“正常”的历史问题，类似银河系的星系从它们形成的时代到现在。这些研究是基于类星体吸收线光谱学技术和更传统的光学和近红外成像以及非常微弱的遥远星系的光谱学技术的结合。研究对象的选择是基于它们在更远的背景类星体的光谱中产生的氢和金属吸收线。类星体的高分辨率光谱学提供了产生吸收的星系的极其详细的物理信息，即使是对于那些仅仅是（使用传统方法）检测的星系，我们目前的技术能力也是有限的。星系的样本，基本上是根据它们的气体横截面来选择的，在构建时没有任何与星系发射的恒星辐射作为时间函数的性质有关的偏差。这些样本代表了一个非常大的宇宙时代范围，从宇宙只有现在年龄的10%到现在。然后将这些信息与直接识别产生吸收线系统的星系的数据结合起来，使用成像和光学和近红外的低色散星系光谱。这些数据提供了恒星数量、光度和相对于类星体视线的几何方向的信息。总的来说，我们可以获得关于星系的化学成分、气相结构、运动学、光度分布、电离状态、空间密度和群集特性作为时间函数的信息。这些方法的结合，所有这些方法都可以使用现有的大型地面望远镜上的仪器来进行，可以构建正常星系自形成以来的详细历史。目前，星系形成和演化理论在很大程度上不受观测的约束，而这项研究的目的是将这一主题置于坚实的经验基础之上。这个奖项是为了表彰在科学和工程领域杰出的年轻教员。该奖项将通过为研究和教育活动提供灵活的支持，提高教师的职业生涯。鼓励与支持研究和教育的工业和机构合作。

9457446 Steidel Over the course of the next several years, a number of inter-related projects will be pursued which address the broad question of the history of "normal", Milky-Way-like galaxies from the epoch of their formation to the present time. The studies are based on a combination of the technique of quasar absorption line spectroscopy and more conventional optical and near-infrared imaging and spectroscopy of very faint, distant galaxies. The objects for study are selected on the basis of their having produced hydrogen and metallic absorption lines in the spectra of even more distant, background quasars. High resolution spectroscopy of the quasars yields extremely detailed physical information on the galaxies producing the absorption, even for galaxies whose mere detection (using conventional methods) strains our technological capabilities at the present time. Samples of galaxies, selected in essence by their gas cross-section, are constructed without any biases related to the nature of stellar radiation being emitted by the galaxies as a function of time. The samples represent a very large range of cosmic epochs, from times when the Universe was only 10% of its current age, to the present. One then combines this information with data that is obtained from direct identification of the galaxies producing the absorption line systems using imaging and low-dispersion galaxy spectroscopy in the optical and the near-infrared. These latter data provide information on the stellar populations, luminosities, and geometrical orientations with respect to the line of sight to the quasars. In total, then, one obtains information on the chemical composition, gas-phase structure, kinematics, luminosity distribution, ionization state, space density, and clustering properties of galaxies as a function of time. The marriage of these methods, all of which can be pursued using currently existing instrumentation on large ground-based telescopes, allows the construct ion of a detailed history of normal galaxies since the time of their formation. Galaxy formation and evolution theories are at present largely unconstrained by observations, and it is the intent of this research effort to place the subject on a firm empirical footing. This award is to recognize an outstanding young faculty member in science and engineering. The award will enhance the career of the faculty member by providing flexible support for research and educational activities. Cooperation with industry and institutions that support research and education is encouraged.