Probing Cosmology with Diffuse Background Radiation Observations

用漫反射背景辐射观测探测宇宙学

• 批准号: RGPIN-2016-04245
• 负责人: Hinshaw, Gary
• 金额: $ 4.37万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614937
• 关键词: Probing; Cosmology; Diffuse; Background; Radiation

Cosmology is the study of the physical universe and our place in it. The questions being addressed are profound: How old is the universe? How did it begin? How will it end? Is it finite or infinite? Just over a decade ago we had only rudimentary knowledge of the age and fate of our universe. Today, thanks to precise observations from an array of high-technology instrumentation, we know the age of the universe to better than 1%: 13.77 billion years. We know the contents of the universe are dominated by dark matter (24%) and dark energy (71%). Ordinary atomic matter makes up only 4.6% of the universe. To the best of our knowledge, the universe is infinite (or at least very large) and it will continue expanding forever, indeed at an ever-faster rate. The full-sky maps of the cosmic microwave background (CMB) radiation produced by NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and ESA's Planck Surveyor Mission played a pivotal role in these advances. As a founding member of the WMAP team I have spent most of my career studying the CMB. I propose to continue these very productive studies Since moving to Canada in 2011, I have helped form a new observational program to study the nature of the dark energy in more detail. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a new "digital" radio telescope being built in British Columbia by a group of Canadian scientists (myself included). CHIME will take a CMB-like approach to measuring dark energy by observing the Baryon Acoustic Oscillation (BAO) scale in diffuse neutral hydrogen (HI) gas via its 21 cm emission. By focusing on diffuse emission, CHIME can survey a vastly larger volume of space than has been previously possible. CHIME is made feasible thanks to rapid advances in radio amplifiers (driven by the cell phone industry) and computing with graphics processing units (driven by the gaming industry). The survey produced by CHIME will allow us to measure the expansion history of the universe and discern if the dark energy deviates from a cosmological constant, a form of vacuum energy first posited by Einstein nearly 100 years ago. In addition to fielding a new telescope, I will continue to pursue a vigorous program of data analysis from more recent CMB experiments. For example, with a group of WMAP team members, we are studying the Planck mission data and comparing it to other pertinent cosmological data. Our focus is to assess the reliability of the Planck data and to understand if all sources of systematic error have been understood and characterized. I am also using the Sunyaev-Zeldovich effect to study the distribution of gas around galaxies to try to understand if violent "feedback" processes early in a galaxy's history act to expel gas from it and quench star formation.

宇宙学是研究物理宇宙和我们在其中的位置的学科。它所要解决的问题是深刻的：宇宙有多老？它是如何开始的？结局会怎样？它是有限的还是无限的？就在十多年前，我们对宇宙的年龄和命运只有初步的了解。今天，由于一系列高科技仪器的精确观测，我们知道宇宙的年龄超过1%：137.7亿年。我们知道宇宙中的物质主要是暗物质（24%）和暗能量（71%）。普通的原子物质只占宇宙的4.6%。据我们所知，宇宙是无限的（或者至少是非常大的），它将永远继续膨胀，而且速度越来越快。美国航天局的威尔金森微波各向异性探测器（WMAP）和欧空局的普朗克勘测者使命产生的宇宙微波背景辐射的全天空图在这些进展中发挥了关键作用。作为WMAP团队的创始成员，我的大部分职业生涯都在研究CMB。我建议继续进行这些富有成效的研究 自从2011年搬到加拿大以来，我帮助建立了一个新的观测计划，以更详细地研究暗能量的性质。加拿大氢强度测绘实验（CHIME）是一个新的“数字”射电望远镜，由一组加拿大科学家（包括我自己）在不列颠哥伦比亚省建造。CHIME将采取类似CMB的方法来测量暗能量，通过其21 cm发射来观察扩散中性氢（HI）气体中的重子声振荡（BAO）尺度。通过专注于漫射发射，CHIME可以测量比以前更大的空间体积。由于无线电放大器（由手机行业驱动）和图形处理单元计算（由游戏行业驱动）的快速发展，CHIME变得可行。CHIME产生的调查将使我们能够测量宇宙的膨胀历史，并辨别暗能量是否偏离宇宙学常数，这是爱因斯坦近100年前首次提出的真空能量形式。 除了配备一台新的望远镜外，我还将继续进行一项有力的计划，对最近的CMB实验进行数据分析。例如，我们正在与WMAP小组的一组成员一起研究普朗克使命的数据，并将其与其他相关的宇宙学数据进行比较。我们的重点是评估普朗克数据的可靠性，并了解是否所有系统误差的来源都已被理解和表征。我也在使用Sunyaev-Zeldovich效应来研究星系周围气体的分布，试图了解星系历史早期的暴力“反馈”过程是否会将气体从星系中排出，并抑制星星的形成。