Collaborative Research: Exploring Star Formation in the Early Universe through Investigations of High-Redshift ISM

AST-0708543/0709235 Wolfe/Prochaska这项由A.Wolfe博士领导的合作将通过应用为本地星际介质（ISM）开发的诊断工具来研究中性气体和高红移年轻恒星之间的关系。 我们所知道的关于高红移星系中星星形成的大部分信息都来自于对它们发射的观测，但是阻尼莱曼α系统（DLAs）是在类星体的吸收中检测到的。 一般来说，这些星系比任何其他在发射中检测到的高红移天体更具代表性。 这项研究将（1）发现和分析超过1000个新的DLAs，为ISM研究确定大量的星系样本，（2）在紫外线中检测到碳-II吸收的DLAs数量增加两倍，以测量气体冷却和加热速率，（3）对来自DLAs中冷中性气体的亚毫米波长范围的碳-II发射进行初步观测，以确定高红移星系的大小和质量，（4）寻找来自DLAs的氢-α发射，绘制电离气体的速度场以寻找星系旋转的证据，（5）测量年轻星系中ISM的温度，密度，分子含量和多相结构，最后，（6）利用绿色班克望远镜通过探测21厘米吸收线的塞曼分裂来测量中红移DLA中的磁场。DLA科学的影响已经稳步增长，超出了类星体吸收线的领域，包括早期宇宙的化学演化和核合成，精细结构常数的变化，以及星系形成关键方面的全球限制。 因此，目前的研究将通过一个先进的网站广泛传播给天文学界，并超越普通教育界。 此外，支持研究生和让本科生接触前沿研究是这些研究人员的主要活动。

AST-0708543/0709235Wolfe/ProchaskaThis collaboration, led by Dr. A.Wolfe, will examine the relationship between neutral gas and young stars at high redshift, by applying diagnostic tools developed for the local interstellar medium (ISM). Most of what we know about star formation in high-redshift galaxies stems from observing them in emission, but damped Lyman-alpha systems (DLAs) are detected in absorption against quasars. In general, these galaxies are more representative than any other high-redshift objects detected in emission. This study will (1) discover and analyze over 1000 new DLAs, identifying a large sample of galaxies for ISM research, (2) triple the number of DLAs with detected carbon-II absorption in the ultraviolet, to measure the gas cooling and heating rates, (3) pursue preliminary observations of carbon-II emission in the sub-millimeter wavelength range, coming from the cold neutral gas in DLAs, to determine the sizes and masses of high-redshift galaxies, (4) search for Hydrogen-alpha emission from DLAs, mapping the velocity field of the ionized gas for evidence of galaxy rotation, (5) measure the temperature, density, molecular content and multi-phase structure of the ISM in young galaxies, and finally, (6) measure magnetic fields in intermediate-redshift DLAs by detecting Zeeman splitting in the 21-cm absorption lines using the Green Bank Telescope.The impact of DLA science has steadily grown beyond the field of quasar absorption lines, to include chemical evolution and nucleosynthesis in the early Universe, variations in the fine-structure constant; and global constraints on critical aspects of galaxy formation. The present research will therefore be widely disseminated to the astronomical population, and beyond to the general education community through an advanced Web site. In addition, support for graduate students and exposing undergraduates to cutting-edge research are staple activities of these researchers.