Intergalactic Archaeology: Decoding the Relics of Reionization in the Intergalactic Medium

第一批光源是在大爆炸后数亿年形成的，结束了天文学家所说的宇宙黑暗时代。在2010年的十年调查中，美国天文界将研究这一时期定为核心科学目标。该项目将通过对用最大的望远镜收集的天文数据应用新的方法来获得对这个纪元和第一批光源的新限制。这些数据将与最先进的超级计算机模型进行比较，以产生对宇宙历史的新见解。这个项目将支持一名博士生的研究，部分支持一名博士后学者，并吸引来自两个拉美裔服务机构的本科生参与尖端天文学研究。准确地确定再电离是如何以及何时发生的，是宇宙学中最重要的悬而未决的问题之一。高z类星体新的大样本统计吸收光谱具有巨大的未开发潜力。本项目将研究z~6类星体光谱中Ly-α吸收的统计性质。通过利用最近此类类星体数量的五倍增长、档案数据、新的方法和模拟，该项目将能够对数百个类星体光谱进行精确测量。这个项目将：1)以远远超过现有方法的精度重建再电离历史，2)测量直到再电离结束阶段星系的电离光子输出，3)测量通过再电离注入星际介质的热量，为了解哪些来源(星系、活动星系核、波普)提供新的见解。3)重新电离宇宙，4)测量类星体寿命的分布，5)对最近发现的年轻类星体的统计样本进行光谱表征。主要目标是提升对星系间介质的定量研究，使其与其他精密宇宙学测量具有同样坚实的方法论和统计学基础。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The first sources of light formed several hundred million years after the Big Bang, ending what astronomers refer to as the cosmic dark ages. In the 2010 Decadal Survey, the US astronomy community designated the study of this epoch as a core science objective. This project will obtain new constraints on this epoch and the first sources of light by applying novel methods to astronomical data collected with the largest telescopes. These data will be compared to state-of-the-art supercomputer models to yield new insights into cosmic history. This project will support the research of a PhD student, partially support a postdoctoral scholar, and engage undergraduates from two hispanic serving institutions in cutting edge astronomical research. Determining exactly how and when reionization occurred are among the most important open questions in cosmology. Absorption spectroscopy of new large statistical samples of high-z quasars has tremendous untapped potential. This project will study the statistical properties of Ly-alpha; absorption in the spectra of z ~ 6 quasars. By leveraging the recent fivefold increase in the number of such quasars, archival data, new methodologies and simulations, this project will enable precise measurements of hundreds of quasar spectra. This project will: 1) reconstruct the reionization history at a precision that far surpasses existing methods, 2) measure the ionizing photon output from galaxies up to the end stages of reionization, 3) measure the amount of heat that was injected into the intergalactic medium by reionization, providing new insights into what sources (galaxies, AGN, Pop. III stars) re-ionized the Universe, 4) measure the distribution of quasar lifetimes, 5) spectroscopically characterize a statistical sample of recently discovered young quasars. The overarching goal is to elevate quantitative study of the intergalactic medium to be on the same solid methodological and statistical footing as other precision cosmological measurements.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.