The Intergalactic Medium at Large Redshifts

星系间大介质红移

• 批准号: 0206067
• 负责人: Wallace L. Sargent
• 金额: $ 40.01万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0206067&HistoricalAwards=false
• 关键词: Intergalactic; Medium; Large; Redshifts

PROPOSAL NO: AST 0206067PI: Sargent, W L WThe past few years have witnessed remarkable progress in understanding the origin and properties of the intergalactic medium, which gives rise to the absorption features known as the ''Lyman alpha forest'' in the spectra of distant quasars. Comparison of the results of high resolution spectroscopy with hydrodynamic cosmological simulations of the high redshift (z ~ 3) universe have shown that the Lyman alpha forest is the observational signature of an extended ionized gas arranged in the shape of filaments and sheets, the ''Cosmic web'', from which galaxies condense. This main reservoir of baryons has properties which can be characterized by gas dynamics (temperature, pressure, ionization state) on a small scale; on larger scales the gas follows the distribution and peculiar motions of the dark matter which dominates the mass content of the universe. Observations of Lyman alpha absorption probe the ionization history and baryon density of the universe as well as the variations in the dark matter distribution which leads to the formation of structure in the universe. The funded work will continue and extend observations and analyses in a program of quasar absorption line studies and a program to detect emission from the Lyman alpha forest clouds using the HIRES and LRIS instruments on the Keck Telescopes.

提案编号：AST 0206067 PI：萨金特，W L W过去几年在理解星系际介质的起源和性质方面取得了显着进展，这导致了遥远类星体光谱中被称为"莱曼α森林"的吸收特征。通过对高红移（z~3）宇宙的高分辨光谱学和流体动力学宇宙学模拟结果的比较，我们发现莱曼α森林是星系凝聚形成的"宇宙网"--一种以丝状和片状排列的扩展电离气体的观测特征。这个重子的主要储存库具有可以在小尺度上由气体动力学（温度、压力、电离状态）表征的性质;在更大尺度上，气体遵循支配宇宙质量含量的暗物质的分布和特殊运动。 对莱曼α吸收的观测可以探测宇宙的电离历史和重子密度，以及暗物质分布的变化，而暗物质分布的变化导致宇宙结构的形成。受资助的工作将继续并扩大类星体吸收线研究计划中的观测和分析，以及使用凯克望远镜上的HIRES和LRIS仪器探测莱曼阿尔法森林云发射的计划。