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

在大爆炸模型中，宇宙开始时处于非常热的状态，物质在这种状态下被电离。这现在被视为宇宙微波背景(CMB)辐射。随着宇宙的膨胀，它变冷了。在后来的阶段，第一批恒星形成了。这导致中性物质在再电离时代(EoR)再次被电离。在以后的时间里，这个极限是由第一批恒星引起的电离来设定的。在第一批恒星之后，第一批星系就形成了。这是一个理论场景，因此需要测量来提供所需的重要细节。该项目的目标是首次从提高采收率中测量中性氢。由于仪器效应，这样的测量是极其困难的。此外，该项目还包括对本科生、研究生和博士后的指导。实践培训提供了对超精密测量的独特介绍，因此这将是一次涉及仪器和数据分析的无与伦比的体验。该项目的目标是测量中性氢的超精细转变。宇宙的历史是通过红移来追溯的，所以红移越高，对应的时间就越早。中巴在红移约1000度时升起。在红移约30时，最丰富的成分是中性原子氢。星系的最大测量红移约为8。据推测，在红移大于8的情况下，这种物质在复合时代(EOR)被恒星重新电离。因此，EOR应该以红移8和30为界。在较早的时候，提高采收率的极限是由CMB引起的离子重组而设定的。EOR可以追溯到第一批恒星和星系形成之前的时间。根据当地的物理条件，谱线既可以在对CMB的吸收中，也可以在发射中。通过测量这条线，可以更详细地确定提高采收率期间宇宙的状态。这是对中巴进行的广泛而持续的研究的补充。该方案将降低由大线宽和高强度前景辐射引起的仪器效应。他们将通过构造一种改进的接收器来实现这一点，该接收器在所研究的红移范围内具有更一致的响应。此外，他们还将研究一种响应更均匀的偶极子设计。这些进步处于电子设计的前沿，因此需要大量的实验室测试，每一次测试都非常耗时。此外，提出者正在改进他们的数据缩减，以进一步减少系统误差的影响。EoR谱的探测将有助于以一种非常重要的、可能是变革性的方式扩大我们对宇宙演化的知识。这将在恒星形成之前的宇宙早期阶段和现在的阶段之间提供一个重要的联系。对学生进行的超精密测量技术培训是独一无二的。与商业公司的互动可能会对大大改进的测试设备的设计产生广泛的影响。

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.