Collaborative Project: A Precision Measurement of the Polarization of the 2.7 K Cosmic Microwave Background Radiation

合作项目：2.7K宇宙微波背景辐射偏振的精确测量

• 批准号: 9802851
• 负责人: Peter Timbie
• 金额: $ 40.31万
• 依托单位: University of Wisconsin-Madison
• 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: 1998-09-01 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9802851&HistoricalAwards=false
• 关键词: Collaborative; Project; Precision; Measurement; Polarization

AST-9802851 Timbie Dr. Timbie and Dr. Ruhl are collaborating on a two-phase program to measure the cosmic microwave background (CMB), first at large angular scales and later at small scales. This program operates in a single millimeter frequency band (26-36 GHz). .Recent measurements of the spectrum and the spatial anisotropy of the 2.7K CMB have dramatically improved our understanding of the early universe. The third characteristic of this radiation, its polarization, has not yet been detected. The amplitude of the linear polarization and its spatial distribution are extremely sensitive to both the source of the temperature anisotropy (density perturbations or gravitational waves) and the ionization history of the universe. The predicted polarization amplitude is less than or equal to 10% of the size of the COBE (Cosmic Microwave Background Explorer) anisotropy signals at 7o. The research team is using new receiver technology with 100 times more sensitivity than previous polarization experiments, as well as a novel instrument design. Detection of polarization will help to: provide details about the formation of structure in the universe; complement CMB temperature anisotropy measurements of cosmological parameters; determine if recombination was instantaneous; determine the redshift of reionization; distinguish between inflation and defect models for structure formation; probe magnetic fields in the early universe and in clusters of galaxies; understand galactic and extragalactic sources of polarized radiation. ***

9802851 Timbie博士和Ruhl博士正在合作一个分两个阶段测量宇宙微波背景的计划，首先测量大角度尺度，然后测量小尺度。该程序在单个毫米频段(26-36 GHz)运行。最近对2.7K CMB的光谱和空间各向异性的测量极大地提高了我们对早期宇宙的理解。这种辐射的第三个特征，即它的偏振，还没有被探测到。线偏振的幅度及其空间分布对温度各向异性(密度扰动或引力波)的来源和宇宙的电离历史都非常敏感。预测的偏振幅度小于或等于COBE(宇宙微波背景探测器)各向异性信号在70o的大小的10%。研究小组正在使用新的接收器技术，其灵敏度是以前偏振实验的100倍，以及一种新颖的仪器设计。对极化的探测将有助于：提供关于宇宙中结构形成的细节；补充宇宙参数的CMB温度各向异性测量；确定复合是否是瞬时的；确定再电离的红移；区分结构形成的膨胀模型和缺陷模型；探测早期宇宙和星系团中的磁场；了解银河系和银河系外极化辐射源。***