Ground-based Observations of Low to Moderate Redshift Damped Lyman Alpha Systems

转折星系的形成和演化需要气体转化为恒星。因此，对星系形成的全面研究需要对宇宙的气体和恒星成分进行正确的描述。研究人员将通过研究背景类星体光谱中的阻尼莱曼-a(DLA)吸收线系统，研究处于低到中等红移的星系的中性气体成分。这项研究将达到对中性气体成分及其性质红移演化的定量理解，并对星系形成的分级模型进行明确的测试。将大量利用现有的和档案数据，以便在各种公共和私人望远镜上进行仔细有针对性的后续观测。较低的红移研究将比较当地气体和高红移DLA，并评估在只跟踪星系恒星成分的研究中难以评估的偏差。基本的测试是可能的，因为有些参数目前只能在红移较低的DLA中测量。除了增进对观测宇宙学特定前沿领域的知识和理解外，该计划还将开发一个基础设施，使社区广泛获得数据。还在计划将这项研究的性质及其一些基本的科学方法传达给特定的其他目标受众，这将得益于该团队碰巧包括来自传统代表性不足群体的个人。*

AST-0307743TurnshekGalaxy formation and evolution require the conversion of gas into stars. A comprehensive study of galaxy formation therefore requires a correct description of both the gaseous and stellar components of the Universe. The investigators will study the neutral gas components of galaxies at low to moderate redshifts, through investigations of damped Lyman-a (DLA) absorption-line systems, seen in the spectra of background quasars. This research will arrive at a quantitative understanding of the redshift evolution of the neutral gas component and its properties, as well as make definitive tests of hierarchical models for galaxy formation. Much use will be made of existing and archival data, allowing for carefully targeted follow-up observations at a variety of public and private telescopes.Lower redshift studies will compare local gas with high redshift DLAs, and evaluate biases that are difficult to assess in studies that track only the stellar components of galaxies. Fundamental tests are possible because there are parameters which can currently only be measured in the lower-redshift DLAs.In addition to advancing knowledge and understanding in specific forefront areas of observational cosmology, this program will develop an infrastructure to make the data widely available to the community. Plans are also underway to convey the nature of this research and some of its fundamental scientific methods to specific other target audiences, which will be helped by the fact that the team already happens to include individuals from traditionally under-represented groups.***