Reconstructing The Cosmic Density Field to Understand the Local Intergalactic Medium and its Relation to Galaxies

重建宇宙密度场以了解当地星系间介质及其与星系的关系

• 批准号: 0908334
• 负责人: Houjun Mo
• 金额: $ 42.83万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908334&HistoricalAwards=false
• 关键词: Reconstructing; Cosmic; Density; Field; Understand

Dr. Mo and his team will use the Sloan Digital Sky Survey (SDSS), a large survey of nearby galaxies, to reconstruct the distribution of dark matter in the local Universe at the present time. With the aid of large gravitational N-body simulations, they will deduce what that matter distribution must have been earlier in cosmic history, before the galaxies began to form their stars. At those early times, normal matter in the form of gas would have been evenly mixed with the dark matter. The team will then use smooth-particle hydrodynamic simulations to follow the combined development of the dark matter and the gas, under various assumptions about how the gas is turned into stars, and how those stars feed energy back into the intergalactic gas. Their aims include testing a currently-popular model, according to which gas is shocked and heated as it falls into massive systems, but flows quietly into smaller galaxies, remaining cold so that it can readily form stars. They will estimate how much gas is associated with various cosmic environments, such as filaments and sheets of galaxies, and examine how metals produced by the nuclear reactions inside stars are fed into the intergalactic gas.A graduate student will be trained by participating in the research, and the team also expects to offer small-scale research projects for undergraduates. The density fields derived from the SDSS catalog, and various catalogs from the simulations, will be made available to the astronomical community. The team will produce three-dimensional maps of the reconstructed distribution of dark matter, luminous galaxies and intergalactic gas, for use in teaching and public outreach.

莫博士和他的团队将使用斯隆数字巡天（SDSS），一个对附近星系的大型调查，来重建目前本地宇宙中暗物质的分布。 在大型引力N体模拟的帮助下，他们将推断出在宇宙历史的早期，在星系开始形成恒星之前，物质分布必须是什么。 在那些早期，气体形式的正常物质会均匀地与暗物质混合。 然后，该团队将使用光滑粒子流体动力学模拟来跟踪暗物质和气体的联合发展，在各种假设下，气体如何变成恒星，以及这些恒星如何将能量反馈到星系际气体中。 他们的目标包括测试当前流行的模型，根据该模型，气体在福尔斯落入大质量系统时受到冲击和加热，但安静地流入较小的星系，保持寒冷，以便容易形成恒星。 他们将估计有多少气体与各种宇宙环境有关，如星系的细丝和薄片，并研究恒星内部核反应产生的金属如何进入星系际气体。研究生将通过参与研究进行培训，该团队还希望为本科生提供小规模的研究项目。 来自SDSS目录的密度场，以及来自模拟的各种目录，将提供给天文学界。 该小组将制作重建的暗物质、发光星系和星系间气体分布的三维地图，供教学和公众宣传使用。