Probing Inflationary Cosmology with CLASS

Thomas Essinger-Hileman博士被授予美国国家科学基金会天文学和天体物理学博士后奖学金，在约翰霍普金斯大学开展研究和教育项目。该研究员的研究项目是利用宇宙大角尺度测量器（CLASS）测量宇宙微波背景（CMB）的偏振。拟议中的研究解决了关于宇宙起源和本质的基本问题，并帮助天体物理学家测试关于宇宙诞生的相互竞争的理论。这样的测量被认为是2010年天文学和天体物理学十年调查的首要科学任务。该项目将有助于创建CMB的高灵敏度极化和温度图，并直接测试非常早期，充满活力的宇宙的暴胀模型。宇宙暴胀会产生引力波背景，其水平与暴胀结束时的真空能量密度直接对应。通过寻找CMB极化中引力波背景的奇偶校验特征，即所谓的“B模式”，CLASS将研究大统一理论（GUT） 10^16 GeV能量尺度上的物理学。相比之下，大型强子对撞机的设计目的是探测高达7 × 10^3 GeV的能量。CLASS将在高海拔地区形成一个多频率天文台，在目前和计划中的地面实验中，它在大角度尺度上针对b模功率谱中的再电离碰撞是独一无二的。PI将领导CLASS的90 GHz接收机的开发、调试和现场校准。这将包括为馈角耦合的单片阵列设计一种新颖的焦平面架构，过渡边缘传感器偏振计，以及结合他自己设计的硅粉滤波器的独特热滤波策略。这个项目更广泛的影响包括一个重要的教育组成部分。该研究员将与约翰霍普金斯大学教育推广中心合作开展一项教育推广计划，在两年的时间里，向一个以非洲裔美国人为主的学区的高中生传达宇宙学方面令人兴奋的发展。随着研究的进展，研究员将通过音频和视频媒体、博客和照片交流研究进展。他将每月与一群10年级和11年级的学生见面，让学生们参与在实验室和智利望远镜上进行的研究。为这个项目开发的演示材料将通过现有的项目，如约翰霍普金斯大学的年度物理博览会，以及通过世界望远镜网站上的互动演示，扩展到更广泛的受众。这个项目望远镜所看到的天空叙事之旅将向广泛的全球观众展示该项目在宇宙学方面的成果。

Dr. Thomas Essinger-Hileman is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at Johns Hopkins University. The fellow's research program is to measure the polarization of the cosmic microwave background (CMB) with the Cosmology Large Angular Scale Surveyor (CLASS). The proposed research addresses fundamental questions of the origin and nature of the Universe and helps astrophysicists test competing theories of the birth of the Universe. Such measurements were regarded a top scientific priority in the 2010 Decadal Survey of Astronomy and Astrophysics.This project will facilitate the creation of high-sensitivity polarization and temperature maps of the CMB and directly test inflationary models of the very early, energetic Universe. Cosmological inflation would produce a gravitational-wave background at a level that directly corresponds with the vacuum energy density at the end of inflation. By looking for the odd-parity signature of a gravitational-wave background in the CMB polarization, the so-called "B modes," CLASS will investigate physics on grand-unification-theory (GUT) energy scales of 10^16 GeV. In contrast, the Large Hadron Collider is designed to probe energies up to 7x10^3 GeV. CLASS will form a multi-frequency observatory at a high-altitude site, and it is unique among current and planned ground-based experiments in aiming at the reionization bump in the B-mode power spectrum at large angular scales. The PI will lead the development, commissioning, and field calibration of the 90 GHz receivers for CLASS. This will include the design of a novel focal plane architecture for monolithic arrays of feedhorn-coupled, transition-edge-sensor polarimeters, as well as unique thermal filtering strategies incorporating silicon-powder filters of his own design. The broader impacts of this project include a significant educational component. The fellow will undertake a program of educational outreach in partnership with the Johns Hopkins Center for Educational Outreach to convey exciting developments in cosmology to high school students in a predominantly African-American school district over a two-year period. As the research progresses, the fellow will communicate developments through audio and video media, weblogs, and photographs. He will meet with a group of 10th- and 11th-graders monthly to engage the students in the research happening in the lab and at the telescope in Chile. The presentation materials developed for this program will then be expanded to reach a broader audience through existing programs such as the annual physics fair at Johns Hopkins, as well as through an interactive presentation on the World Wide Telescope web site. This narrative tour of the sky as seen by project telescopes will present the project's results in cosmology to a broad, global audience.