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

通过 REACH 实验探索宇宙黎明和再电离时代

• 批准号: EP/Y02916X/1
• 负责人: Eloy De Lera Acedo
• 金额: $ 300.94万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FY02916X%2F1
• 关键词: Probing; Cosmic; Dawn; Epoch; Re

How did the Universe transition from a mostly empty volume after the Big Bang to a complex realm of stars, galaxies and other celestial objects? This unknown process occurred during the so-called Cosmic Dawn and the Epoch-of-Reionziation. 21-cm radio-cosmology is the field of research promising to unlock the secrets of the infant Universe by studying radio signals from the most abundant element in the Universe: hydrogen. I request funding to assemble a research team to focus on the detection and study of the elusive 21-cm signal from atomic hydrogen using the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) that I conceived and lead. Radio-interferometers have already placed upper limits on the 21-cm power spectra, while it is the single-antenna experiments, measuring the 21-cm signal averaged across all directions in the sky, the ones that are promising even earlier breakthroughs. The EDGES experiment shook the field in 2018 reporting a cosmological signal twice deeper than expected requiring exotic physics to be explained. This has been contested by several groups amid concerns on the data analysis and potential impact of hardware systematic signals, including recent measurements from the SARAS3 experiment incompatible with the EDGES findings. The contamination from instru- ment systematics is the main bottleneck for "1st generation" 21-cm radio telescopes. Aiming to resolve these concerns, a new experimental approach has emerged over the last 5 years giving birth to a 2nd generation of experiments. REACH is a sky-averaged experiment leading this new wave of instruments, where the focus has shifted to a data-driven hardware and algorithm design focusing on the detection and isolation of instrumental systematic signals. To this end REACH uses a fully Bayesian data pipeline to jointly fit instrument models with models of the sky sig- nals. During this project I will lead the team aiming at a first confident detection and study of the sky-averaged 21-cm line.

宇宙如何从大爆炸后的大部分空体积过渡到一个复杂的恒星，星系和其他天体物体？这个未知的过程发生在所谓的宇宙黎明和重新元素时期。 21-CM无线电系统是通过研究宇宙中最丰富元素的无线电信号来释放婴儿宇宙秘密的研究领域：氢。我要求资金组装一个研究团队，以使用无线电实验对原子氢的难以捉摸的21 cm信号进行检测和研究，以分析我想到和铅的宇宙氢（覆盖率）。射击测量计已经在21厘米的功率谱上放置了上限，而它是单人体实验，测量了在天空中所有方向上平均的21 cm信号，这些信号是有望甚至更早突破的21 cm信号。边缘实验在2018年震撼了该领域，报告的宇宙学信号比需要解释外来物理学的预期深两倍。由于对硬件系统信号的数据分析和潜在影响的担忧，包括SARAS3实验与边缘发现不兼容的最新测量值，这是由几个小组提出的。仪器系统学的污染是“第一代” 21厘米射电望远镜的主要瓶颈。为了解决这些问题，过去5年中出现了一种新的实验方法，诞生了第二代实验。 REACH是一个领导这一新仪器浪潮的天空平均实验，其中焦点已转移到数据驱动的硬件和算法设计，重点是检测和隔离仪器系统信号。在此最终范围内，使用完全贝叶斯的数据管道，将仪器模型与Sky Signals的模型共同拟合。在这个项目中，我将领导团队首先对21厘米的天空平均探测和研究。