CAREER: Measuring the Spectrum of the Cosmic Microwave Background Anisotropy on Angular Scales from 0.15 to 4 Degrees

职业：测量 0.15 至 4 度角尺度上的宇宙微波背景各向异性的光谱

• 批准号: 9732960
• 负责人: Mark Devlin
• 金额: $ 47.75万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-15 至 2004-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9732960&HistoricalAwards=false
• 关键词: CAREER; Measuring; Spectrum; Cosmic; Microwave

9732960 Devlin The main scientific goal of the research is to the study the anisotropy of the Cosmic Microwave Background (CMB) radiation. The CMB is the photon remnant of the Big Bang. The observations of the fluctuations in light intensity of the CMB, and by analyzing the data, the fluctuations in the matter density of the universe at roughly 100,000 years after the big bang can be inferred and this information used to predict the present distribution of matter in the universe. The anisotropy in the CMB provides a key test of models of structure formation of the Universe. The knowledge of the sizes of fluctuations on different angular scales may allow the measurements of cosmological parameters such as the mass density of the universe, the expansion rate, and the baryon density. These parameters will enable us to learn about the universe today, its past, and its future evolution. The focus of the research is an aggressive plan to produce new results in CMB research. The plan is to combine the best aspects of ground-based and balloon borne experiments. The plan is to measure the spectrum of the anisotropy of the CMB on angular scales of from 0.15 to 4 minutes of arc with unprecedented accuracy. The technique of using ground-based observations has already been proven with previous measurements made in Saskatoon, Canada.. These measurements have very long integration times, but are limited by the poor stability of the atmosphere at the site. Balloon borne observations have negligible atmospheric interference, but are limited by integration time. A telescope built for a balloon measurements has been converted into the Mobile Anisotropy Telescope (MAT) which will be used to make observations from a high plateau (5,200 m) in Chile. The atmosphere is stable at this site and integration times can be extended for as long as necessary. The improvement in the measurements will require the use of state-of-the-art detector technology. A 115 element array of transition edge superc onducting bolometric detectors operating at 300 mK will be built for use with the MAT telescope. The array will to used to collect data which will yield independent measurements of the CMB anisotropy over a large fraction of the sky. The net result will be an improvement over the sensitivity of the Saskatoon data by an order of magnitude or more, and an increase in angular resolution by a factor of three. The other goals are to establish a new laboratory for (CMB) research, to develop a research program that incorporates undergraduates and graduates, and to play a central role in developing an astrophysics curriculum. The curriculum will range from courses for general undergraduates and astronomy/astrophysics majors to courses for graduate students. Major progress has already been made along each of these directions. Data on the CMB with a balloon borne telescope has been obtained. Undergraduates will be able to use a newly established laboratory. The undergraduate students will come from a variety of backgrounds, including physics, mechanical engineering and computer science. The development of a new astronomy course for non-majors will be exciting and instructive for both the faculty and students. The plan is to extend the scope of the research and education activities by initiating an outreach program with the City of Philadelphia high schools which will provide area students with supervised projects in observational astronomy. ***

研究的主要科学目标是研究宇宙微波背景辐射的各向异性。宇宙微波背景是宇宙大爆炸的光子残余物。通过对CMB光强度波动的观测，以及对数据的分析，可以推断出大爆炸后大约10万年宇宙物质密度的波动，并利用这些信息来预测宇宙中物质的当前分布。宇宙微波背景的各向异性为宇宙结构形成模型提供了关键的检验。了解不同角度尺度上涨落的大小，可以测量宇宙参数，如宇宙的质量密度、膨胀率和重子密度。这些参数将使我们能够了解宇宙的今天、过去和未来的演变。研究的重点是在CMB研究中取得新成果的积极计划。该计划将结合地面和气球实验的最佳方面。该计划将以前所未有的精度在0.15到4分弧度的角度尺度上测量CMB的各向异性光谱。以前在加拿大萨斯卡通进行的测量已经证明了使用地面观测的技术。这些测量有很长的积分时间，但受到现场大气稳定性差的限制。气球观测的大气干扰可以忽略不计，但受积分时间的限制。为气球测量而建造的望远镜已被转换为移动各向异性望远镜（MAT），该望远镜将用于在智利高原（5200米）进行观测。这个地点的大气是稳定的，积分时间可以根据需要延长。测量的改进将需要使用最先进的探测器技术。一个115元的过渡边缘超导热测量探测器阵列，工作在300 mK，将与MAT望远镜一起使用。该阵列将用于收集数据，这些数据将产生对宇宙微波背景各向异性的独立测量。最终的结果将是比萨斯卡通数据的灵敏度提高一个数量级或更多，并将角分辨率提高三倍。其他目标是建立一个新的CMB研究实验室，制定一个包括本科生和研究生的研究计划，并在开发天体物理学课程中发挥核心作用。课程范围从普通本科生和天文学/天体物理学专业的课程到研究生的课程。在这些方向上已经取得了重大进展。利用气球载望远镜获得了宇宙微波背景的数据。本科生将可以使用新建立的实验室。本科学生将来自不同的背景，包括物理、机械工程和计算机科学。开设一门新的非专业天文学课程对教师和学生来说都是令人兴奋和有益的。该计划旨在扩大研究和教育活动的范围，与费城的高中开展一项外展计划，为当地学生提供观测天文学方面的监督项目。＊＊＊