Probing the Cosmic Dawn and Epoch of Re-ionization with REACH

利用 REACH 探索宇宙黎明和再电离时代

基本信息

批准号：
ST/V004425/1
负责人：
Eloy De Lera Acedo
金额：
$ 88.83万
依托单位：
University of Cambridge
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FV004425%2F1
关键词：
Probing Cosmic Dawn Epoch Re

项目摘要

The Big Bang model for the origin and initial evolution of the Universe is by now a familiar and well-studied research field. The subsequent, late time, evolution of stars and other celestial objects over billions of years is perhaps even better understood. Less is known, however, about the time between these periods (from about 0.35 to 1 billion years after the Big Bang). During this time the Universe transitioned from being a vast volume filled with a cooling neutral gas to become the realm of cosmic objects that we can now observe from Earth.At the beginning the Universe was filled with a hot, dense fog of ionized gas until the continued expansion and cooling allowed electrons and protons to combine and form the first neutral atoms, eg. hydrogen. Eventually, the neutral matter clumped together under the effects of gravity, providing the conditions for nuclear fusion to occur, leading to the birth of the first stars and galaxies (period known as the Cosmic Dawn). Subsequently, these objects heated and re-ionised the surrounding hydrogen in the Universe during the Epoch of Re-ionization.Researchers speculate that electromagnetic signals from those times should be detectable from Earth at frequencies around the FM band and could be used to study the early Universe. Our best estimations indicate that by using a single antenna radio telescope we should be able to detect the elusive radio waves from this period. However, this will require, as a minimum, calibrating the response of the radio receiver to unprecedented levels. Using my experience designing radio sensors for the super telescope Square Kilometre Array and the Hydrogen Epoch of Re-ionization Array, I will focus my work on developing and operating a simple, very stable, easily calibratable sensor of electromagnetic waves capable of detecting these extremely faint theorized signals if operated from a remote radio quiet zone such as desert areas far away from human-made radio signals and interference. This experiment is called REACH (Radio Experiment for the Analysis of Cosmic Hydrogen), and it will aim at opening a window to these early epochs of the Universe by observing radio signals naturally emitted by hydrogen from the semi-desertic region of the Karoo in South Africa. Hydrogen was the raw material forming the very first stars but also these same hydrogen clouds filling the Universe at the time stop us from directly observing the light from these first stars. Thus, we aim to look at these stars through their interaction with the hydrogen clouds in the same way one would infer a landscape by looking at the shadows in the fog covering it.

到目前为止，宇宙起源和初始演变的大爆炸模型是一个熟悉且熟悉的研究领域。在数十亿年中，恒星和其他天体的演变随后的后期，甚至可以更好地理解。然而，在这些时期之间的时间（大爆炸之后约3.35年至10亿年）中，知之甚少。在这段时间里，宇宙从充满冷却中性气体的巨大体积转变为宇宙物体的境界，我们现在可以从地球上观察到。在开始时，宇宙中充满了电离气体的热雾，直到持续的膨胀和冷却允许电子和质子组合和质子组合并形成第一个中性的原子，eg。氢。最终，中性物质在重力的影响下聚集在一起，为发生核融合提供了条件，导致了第一颗恒星和星系的诞生（被称为宇宙黎明时期）。随后，这些物体在重新离子化的时期期间加热并重新定位了宇宙中周围的氢气。研究人员推测，应以FM频段周围的频率从地球上检测到来自那个时代的电磁信号，并且可以用于研究早期宇宙。我们的最佳估计表明，通过使用单个天线射电望远镜，我们应该能够检测到这一时期的难以捉摸的无线电波。但是，这最少需要校准无线电接收器对前所未有的水平的响应。利用我为超级望远镜平方公里阵列设计无线电传感器的经验和重新离子化阵列的氢时代，我将致力于开发和操作一种简单，非常稳定，易于校准的电磁波传感器，能够检测到这些非常淡淡的理论信号，如果从远程的无线电区域进行操作，例如，诸如沙漠无线电区域之类的远离人类无线电界的远处，并划分了人类的Signals anderfection andervection。该实验称为触及（用于分析宇宙氢的无线电实验），它将旨在通过观察来自南非Karoo的半静态区域自然发出的无线电信号来打开宇宙早期时代的窗口。氢是形成第一颗恒星的原材料，但在时间时，这些相同的氢云使我们无法直接观察到这些第一颗恒星的光。因此，我们的目的是通过与氢云的相互作用来查看这些恒星，就像通过观察覆盖雾的阴影来推断景观一样。