First Light In The Universe: Probing the End Of The Dark Ages

宇宙中的第一道曙光：探索黑暗时代的终结

• 批准号: 0205738
• 负责人: Piero Madau
• 金额: $ 22.27万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0205738&HistoricalAwards=false
• 关键词: First; Light; Universe; Probing; End

AST 0205738MadauIn currently popular cosmological scenarios at very early times, the gas within protogalactic halos with masses comparable to those of present-day dwarf ellipticals experienced rapid cooling and fragmentation. These fragments formed massive stars , which in turn synthesized heavy elements, and exploded as Type II supernovae, enriching the surrounding medium. These subgalactic stellar systems then generated the ultraviolet radiation and mechanical energy that reheated and reionized most of the hydrogen in the cosmos. The history of the Universe during and soon after these crucial formative stages is recorded in the thermal state, ionization degree, and chemical composition of the all-pervading intergalactic medium (IGM). Throughout the epoch of structure formation, the IGM becomes clumpy under the influence of gravity, and acts as a source for the gas that accretes, cools, and forms stars within subgalactic fragments, and as a sink for the metal enriched material, energy, and radiation which they eject. The study of the gaseous and stellar content of the high-redshift Universe thus provides invaluable insight into this era and the basic processes that govern the collapse, cooling, and evolution of some of the earliest formed cosmological structures. This theoretical project will study the epoch of .first light, the astrophysics of protogalactic systems, the intergalactic medium and quasar absorbers in the context of current theories of galaxy formation. It will focus on a series of critical questions in each of these interrelated areas: (1) cosmological reionization, (2) the epoch of first light, and (3) protogalaxy halos, SN-driven winds, and the metal enrichment of the IGM. A coordinated approach will be pursued involving theoretical studies of the controlling physical processes, and direct numerical simulation of their effects within the current paradigm for structure formation. The results of this program should aid in the planning for future large observational facilities such as the California Extremely Large Telescope, the Low Frequency Array, the Square Kilometer Array, and the Next Generation Space Telescope.***

在目前流行的宇宙学理论中，在非常早期的时候，原星系晕内的气体质量与今天的矮椭圆相当，经历了快速的冷却和破碎。这些碎片形成了大质量的恒星，这些恒星又合成了重元素，并爆炸成II型超新星，丰富了周围的物质。这些次星系恒星系统产生了紫外线辐射和机械能，使宇宙中的大部分氢重新加热和再电离。宇宙在这些关键形成阶段期间和之后不久的历史记录在无处不在的星系间介质（IGM）的热状态、电离程度和化学成分中。在整个结构形成时期，IGM在重力的影响下变得块状，并作为气体的来源，在亚星系碎片中吸积、冷却和形成恒星，并作为金属富集物质、能量和它们喷射的辐射的汇。因此，对高红移宇宙的气体和恒星含量的研究提供了对这个时代的宝贵见解，以及控制一些最早形成的宇宙结构的坍塌、冷却和演化的基本过程。这个理论项目将在当前星系形成理论的背景下研究第一光时代、原星系系统的天体物理学、星系间介质和类星体吸收体。它将集中在这些相互关联的领域的一系列关键问题上：(1)宇宙再电离，(2)第一光的时代，(3)原星系晕，sn驱动的风，以及IGM的金属富集。将采取一种协调的方法，包括对控制物理过程进行理论研究，并在目前的结构形成范式内对其影响进行直接数值模拟。该计划的结果将有助于规划未来的大型观测设施，如加州超大望远镜、低频阵列、平方公里阵列和下一代太空望远镜