Collaborative Research: A Better Measurement of the Primordial Helium Abundance

合作研究：更好地测量原始氦丰度

• 批准号: 2205864
• 负责人: Evan Skillman
• 金额: $ 40.96万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2205864&HistoricalAwards=false
• 关键词: Collaborative; Research; Better; Measurement; Primordial

Within five minutes after the Big Bang, during primordial nucleosynthesis, almost all of the helium in the universe was produced. The production of that primordial helium depends on the content and interactions of the universe at that time. This makes a precise measurement of the amount of primordial helium of fundamental importance for testing models of new physics. Using observations of more than 40 metal-poor dwarf galaxies, this collaboration between scientists at the University of Minnesota, Gonzaga University, and The Ohio State University, will determine the primordial helium abundance with unprecedented precision, providing a fundamental test of models of new physics beyond the standard model. This program will have broader impacts through training graduate students, engaging undergraduates in research, and inspiring public interest in science. The public outreach components of this program consist of continuing the Universe in the Park program in the state of Minnesota, the use of the Ohio State University Arne Slettebak Planetarium to reach economically disadvantaged (and minority-majority) urban schools in Columbus and many rural schools in Ohio, and enhanced participation in the Science in Action! program for elementary school students in the Spokane, WA area, targeting schools with the most underserved and disadvantaged populations.Building on several recent investments and breakthroughs, it is now possible to reduce the observational uncertainty on the primordial helium abundance to below 1%, translating to an uncertainty of approximately 3% on the number of neutrino flavors. The Multi-Object Double Spectrographs (MODS) on the Large Binocular Telescope (LBT) enable the simultaneous observation of multiple hydrogen and helium recombination lines necessary for high-fidelity measurements of nebular helium abundances. This program will combine LBT/MODS spectra of metal-poor galaxies with near-infrared spectra and use an improved, sophisticated analysis methodology to determine helium abundances of individual targets with uncertainties of approximately 2%. With new observations of more than 40 metal-poor galaxies, the team will measure a value for the primordial helium abundance with an uncertainty of approximately 0.5%. This project takes advantage of the recent discoveries of many extremely metal-poor galaxies, access to sensitive new instruments on large telescopes, and increasingly sophisticated abundance analysis methodologies. A higher precision measurement of the primordial helium abundance will provide a strong constraint on many proposed models extending the standard model.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.

在大爆炸后的五分钟内，在原始核合成过程中，宇宙中几乎所有的氦都产生了。原始氦的产生取决于当时宇宙的内容和相互作用。这使得精确测量原始氦的数量对于测试新物理模型至关重要。利用对40多个贫金属矮星系的观测，明尼苏达大学，贡扎加大学和俄亥俄州州立大学的科学家之间的这种合作将以前所未有的精度确定原始氦丰度，为超越标准模型的新物理模型提供基本测试。该计划将通过培养研究生，让本科生参与研究以及激发公众对科学的兴趣来产生更广泛的影响。该计划的公共外展部分包括继续在明尼苏达州的宇宙公园计划，使用俄亥俄州州立大学阿恩Slettebak天文馆，以达到经济上处于不利地位（和少数民族占多数）的城市学校在哥伦布和许多农村学校在俄亥俄州，并加强参与科学在行动！在最近的几项投资和突破的基础上，现在有可能将原始氦丰度的观测不确定性降低到1%以下，转化为中微子口味数量的不确定性约为3%。大型双筒望远镜（LBT）上的多目标双光谱仪（MODS）能够同时观测星云氦丰度高保真测量所需的多条氢和氦复合线。该计划将把贫金属星系的LBT/MODS光谱与近红外光谱相联合收割机，并使用改进的复杂分析方法来确定单个目标的氦丰度，其不确定性约为2%。通过对40多个贫金属星系的新观测，该团队将测量原始氦丰度的值，其不确定性约为0.5%。该项目利用了最近发现的许多极贫金属星系、大型望远镜上的灵敏新仪器以及日益复杂的丰度分析方法。原始氦丰度的更高精度测量将为许多扩展标准模型的拟议模型提供强有力的约束。该奖项反映了NSF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。