Following the Universe from Dark to Light

跟随宇宙从黑暗到光明

• 批准号: 0206299
• 负责人: Renyue Cen
• 金额: $ 36.88万
• 依托单位: Princeton University
• 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: 2002-09-15 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0206299&HistoricalAwards=false
• 关键词: Following; Universe; Dark; Light

AST 0206299CenThe formation and evolution of cosmic structures, including galaxies, clusters of galaxies and large-scale structure, are fundamental problems of modern cosmology. While the Big Bang picture of how the Universe began is generally accepted, the details of how and when structures developed and formed are in hot debate. On scales larger than clusters of galaxies (10 million light years across) it is generally believed that gravity is the dominant force and structures grow from small initial seeds planted in the very early universe ( 1 second since the Big Bang), because gravity is attractive and unstable. However, on smaller scales gas hydrodynamics, microphysics (i.e., forces on atomic scales) and star formation processes play progressively more important roles in shaping and determining when galaxies form and how they evolve; the picture at these smaller scales is much less clear. The radiation field, especially, the ultra-violet radiation that is capable of ionizing atomic hydrogen must play a very important role in these processes. In particular, it determines when atomic hydrogen is fully ionized and the universe is cleared of hydrogen "fog" and becomes transparent to distant sources. This epoch has been characterized as the "end of the dark ages". Since radiation controls the evolution of the thermodynamic state of the gas, a fraction of which is subsequently incorporated into stars, it is essential to include radiation hydrodynamics in full detail in cosmological computer simulations in order to provide answers to many of the important questions in modern cosmology. This is a formidable task to tackle even with the fastest supercomputers today. Dr. Cen and his collaborators have developed an efficient way to compute this complicated situation and begun to carry out a program that should help provide some clues about how the radiation field and the matter evolve with time.***

AST 0206299 Centhe的形成和宇宙结构的演变，包括星系，星系簇和大规模结构，是现代宇宙学的基本问题。尽管普遍接受了宇宙如何开始的大爆炸图片，但结构如何以及如何形成结构的细节仍在热门辩论中。在大于星系簇（遍历一千万光年）的尺度上，人们通常认为重力是主要的力量，结构是从早期大学中种植的小初始种子（自大爆炸以来1秒）生长，因为重力是有吸引力且不稳定的。但是，在较小的尺度上，气体流体力学，微物理（即原子尺度上的力）和恒星形成过程在塑造和确定星系何时形成以及它们如何发展方面逐渐越来越重要。 在这些较小的尺度上的图片还不清楚。 尤其是辐射场，能够电离原子氢的超紫色辐射必须在这些过程中起着非常重要的作用。 特别是，它决定了何时完全离子化原子氢，并清除宇宙的氢“雾”，并变得透明地对遥远的来源。这个时代被描述为“黑暗时代的末日”。 由于辐射控制气体的热力学状态的演变，其中一部分被纳入恒星，因此必须在宇宙计算机模拟中详细介绍辐射流体动力学，以便为现代宇宙学中的许多重要问题提供答案。即使今天使用最快的超级计算机，这是解决问题的艰巨任务。 Cen博士及其合作者已经开发了一种有效的方法来计算这种复杂情况，并开始执行一项计划，该计划应有助于提供一些有关辐射领域和问题如何随着时间而演变的线索。***