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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=653604
• 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.**

宇宙学是对物理宇宙以及我们在其中的地位的研究。所解决的问题是深刻的：宇宙有多少年了？事情是怎么开始的？结局会如何呢？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还只有初步的了解。 如今，凭借一系列高科技仪器的精确观测，我们对宇宙年龄的了解精确到了 1%：137.7 亿年。我们知道宇宙的内容主要是暗物质（24%）和暗能量（71%）。普通原子物质仅占宇宙的4.6%。据我们所知，宇宙是无限的（或者至少非常大），并且它将永远继续膨胀，甚至以越来越快的速度膨胀。由 NASA 威尔金森微波各向异性探测器 (WMAP) 和 ESA 普朗克测量任务生成的宇宙微波背景 (CMB) 辐射全天图在这些进展中发挥了关键作用。作为 WMAP 团队的创始成员，我职业生涯的大部分时间都在研究 CMB。我建议继续这些非常富有成效的研究***自 2011 年搬到加拿大以来，我帮助制定了一个新的观测计划，以更详细地研究暗能量的本质。 加拿大氢强度测绘实验（CHIME）是由一群加拿大科学家（包括我本人）在不列颠哥伦比亚省建造的新型“数字”射电望远镜。 CHIME 将采用类似 CMB 的方法，通过 21 厘米发射来观察扩散中性氢 (HI) 气体中的重子声振荡 (BAO) 尺度，从而测量暗能量。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（由手机行业推动）和图形处理单元计算（由游戏行业推动）的快速发展，CHIME 变得可行。 CHIME 进行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，宇宙学常数是爱因斯坦在近 100 年前首次提出的一种真空能量形式。 ****除了部署一台新望远镜外，我还将继续开展一项积极的计划，对最近的宇宙微波背景实验进行数据分析。 例如，我们正在与一组 WMAP 团队成员一起研究普朗克任务数据，并将其与其他相关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来源都已被理解和表征。 我还利用孙亚耶夫-泽尔多维奇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剧烈“反馈”过程是否会排出气体并抑制恒星形成。 **