Collaborative Research: Detecting the First Light and Reionization of the Universe using Advanced Radio Instrumentation

合作研究：使用先进无线电仪器探测宇宙的第一束光和再电离

• 批准号: 1609450
• 负责人: Judd Bowman
• 金额: $ 62.1万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1609450&HistoricalAwards=false
• 关键词: Collaborative; Research; Detecting; First; Light

In the Big Bang model, the universe started in a very hot state in which the material was ionized. This is now seen as the Cosmic Microwave Background (CMB) radiation. As the universe expanded, it cooled. At later stages, the first stars formed. These caused the neutral material to be ionized again, in the Epoch of Reionization (EoR). At later times, the limit is set by the ionization caused by the first stars. After the first stars, the first galaxies formed. This is a theoretical scenario, so measurements are needed to provide important details needed. The goal of this project is the first measurement of neutral hydrogen from the EoR. Such a measurement is extremely difficult because of instrumental effects. In addition, this project includes the mentoring of undergraduate, graduate and postdoctoral students. The hands-on training provides a unique introduction to ultra-precise measurements, so this will be an unequaled experience involving instrumentation and data analysis. The goal of this project is the measurement of the hyperfine transition of neutral hydrogen. The history of the universe is traced by redshifts, so higher redshifts correspond to earlier times. The CMB arose at a redshift of about 1000. At redshifts of about 30, the most abundant constituent is neutral atomic hydrogen. The highest measured redshift for a galaxy is about 8. Presumably, at redshifts higher than 8, this material was reionized by stars, during the Epoch of Recombination (EoR). Thus the EoR should be bounded by redshifts 8 and 30. At earlier times the limit to the EoR is set by the recombination of ions caused by the CMB. The EoR allows a look back to a time before the first stars and galaxies formed. Depending on the local physical conditions, the spectral line can be either in absorption against the CMB or in emission. Though a measurement of this line, the state of the universe during the EoR can be determined in more detail. This complements the extensive, ongoing studies of the CMB. The proposers will lower the instrumental effects cause by the large linewidth and the high intensity of foreground radiation. They will accomplish this by constructing an improved receiver with a more uniform response over the range of redshifts studied. In addition they will investigate a dipole design that has a more uniform response. These advances are at the forefront of electronics design, and so require a large number of laboratory tests, each of which is very time-consuming. In addition, the proposers are improving their data reductions to further reduce the effect of systematic errors. The detection of the EoR spectrum will serve to expand our knowledge of the evolution of the universe in a very significant, perhaps transformational, fashion. This will provide an important link between the early stages of the universe, before stars formed, and the present stage. The training of students in the techniques of ultra-precise measurements is unique. The interaction with commercial firms may have wide-ranging implications for the design of much improved test equipment.

在大爆炸模型中，宇宙开始于一个非常热的状态，在这个状态下，物质被电离。这被称为宇宙微波背景辐射（CMB）。 随着宇宙的膨胀，它冷却了。在后期阶段，第一批恒星形成。这导致中性物质在再电离时代（EoR）再次电离。在以后的时间里，极限由第一批恒星引起的电离决定。 在第一批恒星之后，第一批星系形成了。这是一个理论场景，因此需要测量以提供所需的重要细节。 该项目的目标是首次测量EoR中的中性氢。由于仪器效应，这种测量是极其困难的。此外，该项目还包括指导本科生、研究生和博士后学生。实践培训提供了对超精密测量的独特介绍，因此这将是涉及仪器和数据分析的无与伦比的体验。本项目的目标是测量中性氢的超精细跃迁。宇宙的历史是由红移来追踪的，所以更高的红移对应着更早的时间。宇宙微波背景辐射的红移约为1000。在红移约为30时，最丰富的成分是中性原子氢。星系的最高测量红移约为8。据推测，在红移高于8时，这种物质在电离时期（EoR）被恒星重新电离。因此，EoR应该以红移8和30为界。在早期，EoR的极限是由CMB引起的离子复合设定的。EoR允许回顾第一批恒星和星系形成之前的时间。根据当地的物理条件，光谱线可以是吸收的CMB或发射。通过测量这条线，可以更详细地确定EoR期间宇宙的状态。这是对资本市场管理局正在进行的广泛研究的补充。提出的方案将降低由于大线宽和高强度的前景辐射所引起的仪器效应。他们将通过构建一种改进的接收器来实现这一目标，该接收器在所研究的红移范围内具有更均匀的响应。此外，他们还将研究具有更均匀响应的偶极子设计。这些进步处于电子设计的最前沿，因此需要大量的实验室测试，每一项测试都非常耗时。此外，提议者正在改进其数据简化，以进一步减少系统误差的影响。对EoR光谱的探测将有助于以一种非常重要的、也许是变革性的方式扩大我们对宇宙演化的认识。这将为恒星形成之前的宇宙早期阶段和现在的阶段提供一个重要的联系。学生在超精密测量技术的培训是独一无二的。与商业公司的相互作用可能对改进测试设备的设计产生广泛的影响。

项目成果

Validation of the EDGES Low-band Antenna Beam Model

• DOI: 10.3847/1538-3881/abfdab
• 发表时间: 2021-02
• 期刊: The Astronomical Journal
• 作者: N. Mahesh;J. Bowman;T. Mozdzen;A. Rogers;R. Monsalve;S. Murray;David Lewis