The Structure of the Gaseous Cosmic Web

AST-0506845 Rauch星系际介质（IGM）的宇宙学模拟和观测现在表明，在整个宇宙历史中，大多数重子物质仍然以星系际气体的形式存在，从未进入星系和恒星。 由于气体是非常稀薄和空间扩展，在金属丰度，温度，运动学和电离状态的IGM的变化可以持续很长一段时间。 对背景类星体光谱中IGM引起的吸收的观测揭示了引起这种扰动的各种天体物理过程的微妙特征。 这个项目将研究高红移气体宇宙网的一般结构，特别强调星系与IGM之间的相互作用。 对吸收系统的高质量、高分辨率观测将用于寻找星际风和星系间风的运动学特征，而来自密集类星体视线的数据将用于测量小尺度密度场，并确定湍流能量和整体运动。 这项工作的很大一部分将旨在通过观察IGM的辉光来拍摄高红移中性氢的一般分布图像。该项目包括为学生提供多层次的教育和实践经验，特别强调洛杉矶地区大学的本科生。 学生将获得专业天文台工作的第一手经验，包括与工作人员一起前往南美洲观察，并将完成一个独立的项目。

AST-0506845RauchCosmological simulations and observations of the intergalactic medium (IGM) are now indicating that most of the baryonic matter throughout the history of the Universe has remained in the form of intergalactic gas and never made it into galaxies and stars. Since the gas is very tenuous and spatially extended, changes in the metallicity, temperature, kinematics and ionization state of the IGM can persist for long periods. Observations of the absorption caused by the IGM in the spectra of background quasars reveal the often-subtle signatures of the various astrophysical processes that cause such disturbances. This project will study the general structure of the gaseous cosmic web at high redshift, with particular emphasis on the interactions between galaxies and the IGM. High-quality, high-resolution observations of absorption systems will be used to search for the kinematic signature of interstellar and intergalactic winds, while data from closely spaced quasar lines of sight will be used to measure the small scale density field and to determine the turbulent energy and bulk motions. A large part of the effort will be aimed at taking an image of the general distribution of neutral hydrogen at high redshift by seeing the glow from the IGM.The project includes multi-level educational and practical experiences for students, with particular emphasis on undergraduates from colleges in the Los Angeles area. Students will get first-hand experience of a working professional observatory, including observing trips with staff members to South America, and will be expected to complete a self-contained project.