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-2022-05216
• 负责人: Hinshaw, Gary
• 金额: $ 2.99万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763001
• 关键词: Probing; Cosmology; Diffuse; Background; Radiation

The long--term objective of my research program is to understand the origin and evolution of the universe, and to shed light on the physics of dark matter and dark energy. In collaboration with a number of other astrophysics researchers, I design, build, and operate special purpose telescopes that collect radio and microwave signals from our own galaxy - the Milky Way - and from more distant sources, some as far away as the edge of the observable universe. The data we collect comprises a valuable fossil record of conditions in the younger universe, and help us tease out how the universe formed and evolved. Existing cosmological observations have pointed to the existence of dark matter: a form of matter which does not occupy the Periodic Table of the elements; and to dark energy, which could be energy associated with the vacuum of free space itself, as posited by quantum theory. The bulk of my proposed research effort is devoted to building and operating two new telescopes: the Canadian Hydrogen Intensity Mapping Experiment (CHIME), and the Canadian Galactic Emission Mapper (CGEM), both of which are or will be located at the Dominion Radio Astrophysical Observatory, located just south of Penticton British Columbia. CHIME is a novel and complex radio telescope comprised of 4 co-linear cylindrical reflectors with 2048 receiving elements. Its primary goal is to characterize dark energy by measuring the expansion history of the universe in the redshift range z=0.8-2.5, when the universe was roughly half its present age. CHIME recently detected cosmological 21 cm emission in cross correlation with data from the Sloan Digital Sky Survey, an important milestone in the path to characterizing the dark energy. Continuing the analysis of CHIME data is a major element of my proposed research. CGEM is to be a nimble 4-metre scanning telescope which will survey the northern sky at a frequency of ~10 GHz to map polarized synchrotron emission in the Milky Way. This signal is an important source of foreground confusion for cosmic microwave background (CMB) experiments that are searching for evidence of primordial gravitational waves produced a fraction of a second after the Big Bang, by a hypothesized period of cosmic inflation. If present, the gravity wave background would produce a curl-like pattern in the CMB polarization, but existing upper limits on such a signal already indicate that it will be foreground dominated at all frequencies, hence it is crucially important to have well-characterized foreground measurements over a range of frequencies spanning the CMB frequency "window" in order to disentangle the CMB and foreground signals. This pair of relatively small astrophysics projects are akin to "tabletop" experiments in laboratory physics. Designed and purpose built in-house, but with very high-profile science goals, they attract very talented HQP and serve as ideal training grounds for students seeking to become well-rounded scientists.

我的研究计划的长期目标是了解宇宙的起源和演化，并阐明暗物质和暗能量的物理学。我与许多其他天体物理学研究人员合作，设计、建造和操作特殊用途望远镜，这些望远镜收集来自我们自己的银河系以及更遥远的来源（其中一些远至边缘）的无线电和微波信号。可观测宇宙。我们收集的数据包括年轻宇宙条件的宝贵化石记录，并帮助我们梳理宇宙如何形成和演化。现有的宇宙学观测已经指出了暗物质的存在：一种不占据元素周期表的物质形式;以及暗能量，这可能是与自由空间本身的真空相关的能量，正如量子理论所假设的那样。我提出的大部分研究工作都致力于建造和操作两个新的望远镜：加拿大氢强度测绘实验（CHIME）和加拿大银河系发射测绘仪（CGEM），这两个望远镜都位于或将位于自治领射电天体物理观测站，位于彭蒂克顿南部的不列颠哥伦比亚省。CHIME是一种新颖而复杂的射电望远镜，由4个共线柱面反射镜和2048个接收单元组成。它的主要目标是通过测量红移范围z=0.8-2.5的宇宙膨胀历史来表征暗能量，当时宇宙大约是现在年龄的一半。CHIME最近检测到宇宙学21厘米发射与斯隆数字巡天的数据互相关，这是表征暗能量的重要里程碑。继续分析CHIME数据是我提出的研究的一个主要因素。CGEM将是一个灵活的4米扫描望远镜，它将以~10千兆赫的频率观测北方天空，以绘制银河系中的偏振同步辐射图。这个信号是宇宙微波背景（CMB）实验前景混乱的重要来源，这些实验正在寻找大爆炸后几分之一秒产生的原始引力波的证据，这是一个假设的宇宙膨胀时期。如果存在，重力波背景将在CMB极化中产生卷曲状图案，但此类信号的现有上限已经表明它将在所有频率下以前景为主，因此在整个频率范围内进行良好表征的前景测量至关重要为了解开CMB和前景信号的纠缠，跨越CMB频率“窗口”的频率范围。这两个相对较小的天体物理学项目类似于实验室物理学中的“桌面”实验。内部设计和专门建造，但具有非常高调的科学目标，它们吸引了非常有才华的HQP，并成为寻求成为全面发展的科学家的学生的理想培训场所。