Connecting Dwarf Galaxies, Metal Poor Stars, and the Origins of the Elements

恒星的表面含有其诞生云化学成分的化石指纹，贫金属恒星作为银河系形成和组装历史的示踪剂特别重要。此外，贫金属恒星对于理解元素的起源非常重要，因为很少有核合成事件会对它们的化学成分做出贡献。在未来十年的大型高分辨率光谱、光度和天体测量调查中，将在整个银河系中发现具有有趣起源和动力学的贫金属恒星样本。更高精度的分析将揭示它们的详细组成，使我们能够打破恒星和星系建模中的简并，探索它们的起源并更好地了解元素的形成。这项研究计划建立在我在恒星光谱学方面的专业知识和我与原始调查的成功合作，以寻找稀有的贫金属恒星，导致两个长期目标：（1）寻找和分析整个银河系和矮星系中的贫金属恒星-对银河系和附近卫星中贫金属恒星的研究表明，由于一系列的化学物质，（简并）星系和恒星模型假设。需要更大的统计样本来打破这些简并并绘制贫金属的银河系。(2)理解重r过程元素的起源-元素的起源仍然是物理学中未解决的重大问题之一，尽管一个重大突破是在中子星星合并中发现了r过程核合成，作为无处不在的r过程位点的补充。需要对在各种环境中形成的贫金属恒星进行比较，以限制这些核合成途径。这项研究计划将使用双子座天文台的GRACES和即将推出的GHOST摄谱仪来获得贫金属恒星的高分辨率（R> 50，000）光谱; GHOST对于r过程元素谱线的450 nm以下的光谱特别必要。该计划还将使用来自即将到来的WEAVE光谱调查的贫金属恒星（约3000个目标）的光谱。因此，这是一个激动人心的时刻，发现和分析大量的贫金属恒星，在各种星系环境（银河系隆起，平面，球状星团，流，并在矮星系）。我的研究计划的影响将是更好地了解重元素的起源和贫金属星系的组装历史，从而改进星系和恒星建模。 该计划为HQP提供了观测和理论天体物理学的培训机会，以及开发新数据分析方法的独特机会（例如，机器学习算法）并参与仪器开发（例如，GHOST的科学验证），从而为未来的加拿大设施做好准备（例如，TMT、MSE或等同物）。

The surfaces of stars contain a fossil fingerprint of the chemical composition of their birth clouds, and metal-poor stars are particularly important as tracers of the formation and assembly history of the Galaxy. Moreover, metal-poor stars are important for understanding the origins of the elements given that few nucleosynthetic events would have contributed to their chemical compositions. In the upcoming decade of large high-resolution spectroscopic, photometric, and astrometric surveys, samples of metal-poor stars with interesting origins and dynamics will be discovered throughout the Milky Way. Higher precision analyses will reveal their detailed compositions, allowing us to break degeneracies in stellar and galaxy modeling, to explore their origins and better understand the formation of the elements. This research program builds on my expertise in stellar spectroscopy and my successful collaboration with the Pristine survey to find rare metal-poor stars, leading to two long term goals: (1) Finding and analyzing metal-poor stars throughout the Milky Way and dwarf galaxies - Studies of metal-poor stars in the Milky Way and nearby satellites have shown chemical abundance patterns that differ due to a range of (degenerate) galactic and stellar modeling assumptions. Larger statistical samples are required to break those degeneracies and map the metal-poor Milky Way. (2) Understanding the origins of heavy r-process elements - The origin of the elements remains one of the great unsolved problems in physics, although a major breakthrough came with the discovery of r-process nucleosynthesis in a neutron star merger, as an addition to a ubiquitous r-process site. A comparison of metal-poor stars that formed in a variety of environments is needed to constrain these nucleosynthetic pathways. This research program will use the Gemini Observatory GRACES and upcoming GHOST spectrographs for high resolution (R>50,000) spectra of metal-poor stars; GHOST is particularly necessary for spectra below 450 nm for r-process element spectral lines. This program will also use spectra of metal-poor stars (~3000 targets) from the upcoming WEAVE spectroscopic survey. Therefore, this is an exciting time for the discovery and analysis of a large number of metal poor stars, in a variety of galactic environments (Galactic bulge, plane, globular clusters, streams, and in dwarf galaxies). The impact of my research program will be a better understanding of the origin of the heavy elements and the assembly history of the metal-poor Galaxy, leading to improvements in galaxy and stellar modeling. This program provides training opportunities for HQP in observational and theoretical astrophysics, and unique opportunities to develop new data analysis methodologies (e.g., machine learning algorithms) and to be involved in instrumentation developments (e.g., science verification for GHOST), thereby preparing for future Canadian facilities (e.g., TMT, MSE, or equivalents).