Probing Cosmic Dawn with End-to-End Forward Models

对中性氢的直接观测仍然是“宇宙黎明”号最有希望的探测。该项目将结合美国主导的两个实验的最先进的观测结果：探测全球再电离时代（EoR）信号的全球实验（EDGES）和干涉测量氢再电离时代阵列（HERA）。对HERA数据的分析将区分对EDGES结果的奇异解释，包括早期的无线电噪声黑洞和超越标准模型的新暗物质候选者。在更广泛的层面上，拟议的项目将提供一个共同的框架，以结合不同的数据集，集中在宇宙黎明号上，提高物理解释的可靠性和能力。该项目将在一所致力于为来自非传统背景的学生（如归国学生、第一代学生和老学生）提供服务的大学进行，并将让学生参与非传统本科生项目的成功研究经验。宇宙黎明时代跨越了12到30的红移，包括暗物质晕的引力坍缩和第一批恒星和星系的诞生，对星系演化和宇宙学都有深远的影响。聚焦于50-100 MHz的频率，在此范围内，EDGES已经报告了第一批恒星的第一个证据，该计划将通过定义模块化的端到端统计正演模型来实现一个全新的范式，以解释系统学。这种正演模型是解释系统残差及其对天体物理学和宇宙学后验约束的影响的唯一严格方法。这些正演模型将单独或联合应用于即将到来的第三代EDGES实验数据和完成的HERA II阶段阵列的第一批数据，从而产生迄今为止最严格的物理推断。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Direct observations of neutral hydrogen remain the most promising probes of "Cosmic Dawn". This project will combine state-of-the-art observations from two US-led experiments: the global Experiment to Detect the Global Epoch of Reionization (EoR) Signal (EDGES), and the interferometric Hydrogen Epoch of Reionization Array (HERA). The analysis of HERA data will discriminate between exotic explanations of EDGES’ results, including early radio-loud black holes and novel dark matter candidates beyond the standard model. On a broader level, the proposed project will deliver a common framework for combining different datasets focusing on Cosmic Dawn, increasing both the reliability and power of physical interpretations. This project will take place at a university that has a strong commitment to serving students from non-traditional backgrounds such as returning, first generation, and veteran students and will involve students in the successful Research Experiences for Non-Traditional Undergraduates program.The epoch of Cosmic Dawn, spanning a redshift of 12 to 30, encompasses the gravitational collapse of dark matter halos and the birth of the first stars and galaxies, and has far-reaching implications for both galaxy evolution and cosmology. Focusing on frequencies of 50-100 MHz – within which the first evidence for the first stars has been reported by EDGES, this program will implement a fundamentally new paradigm to account for systematics by defining modular end-to-end statistical forward models. Such forward models are the only rigorous way to account for systematic residuals and their effect on posterior constraints of astrophysics and cosmology. These forward models will be applied – both in isolation, and jointly – to forthcoming data from the third-generation EDGES experiment and the first data from the completed HERA Phase II array, yielding the most stringent physical inference to date during this epoch.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.