Feedback from the First Stars: Chemical Abundances in the First Billion Years after the Big Bang

来自第一代恒星的反馈：大爆炸后最初十亿年的化学丰度

• 批准号: 1109115
• 负责人: Robert Simcoe
• 金额: $ 41.37万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1109115&HistoricalAwards=false
• 关键词: Feedback; First; Stars; Chemical; Abundances

A great deal of work remains to understand how the first stars in the Universe formed and how their formation and life cycles affected the formation of the first galaxies in the Universe. Understanding these essential details will provide important clues to understanding the formation and life history of our own Galaxy and many others. This project aims to track the time history of heavy chemical elements in the intergalactic medium (IGM) at very high redshift. Because most researchers believe that heating from supernovae and/or active galactic nuclei (AGN) played a vital role in galaxy assembly, the principal investigator (PI) has chosen to study the heavy elements, which are a byproduct of this heating "feedback." The PI will address the following specific scientific questions: (1) Is there a decline in the C IV abundance as the epoch of reionization is approached? (2) Is there a change in the ionization structure of heavy element systems at redshift around 6? (3) Do the large differences in absorption properties between QSO sightlines at redshift 6 reflect cosmic variance or a signature of stochastic early star formation? (4) What mechanism populates galaxy haloes with cold baryons (seen in Mg II) at early times?The broader impacts of this project include important educational components. A graduate student will be supported for the three years of this grant, and the PI works closely with his institution to mentor undergraduates in research and astronomical observing activities. The PI also has an excellent track record in working with students from groups underrepresented in the physical sciences.

仍然有很多工作要了解宇宙中的第一批恒星如何形成，以及它们的形成和生命周期如何影响宇宙中第一个星系的形成。 了解这些基本细节将为了解我们自己星系和许多其他许多人的形成和生活历史提供重要的线索。 该项目的目的是在非常高的红移时跟踪层间培养基（IGM）中重型化学元素的时间历史。 由于大多数研究人员认为，超新星和/或主动银河核（AGN）在星系组装中发挥了至关重要的作用，因此首席研究者（PI）选择研究重型元素，这些元素是这种加热“反馈”的副产品。 PI将解决以下具体科学问题：（1）随着电离时代的接近，C IV的丰度是否会下降？ （2）在6日左右，红移时重元系统的电离结构发生了变化吗？ （3）红移6处的QSO视线之间的吸收特性差异是否反映宇宙方差或随机早期恒星形成的标志？ （4）哪些机制在早期使用冷bary子（在MG II中看到）填充了星系光环？该项目的更广泛影响包括重要的教育组成部分。 这笔赠款的三年将支持一名研究生，PI与他的机构紧密合作，以指导研究和天文观察活动。 PI在与物理科学领域不足的小组的学生合作方面还拥有出色的记录。