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

恒星的表面含有其诞生云的化学成分的化石指纹，而金属贫乏的恒星作为银河系形成和组装历史的示踪剂尤为重要。此外，缺乏金属的恒星对于理解元素的起源很重要，因为很少有核合成事件会对它们的化学成分产生影响。在未来十年的大规模高分辨率光谱、光度学和天体测量学调查中，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模型中的简并，探索它们的起源，更好地理解元素的形成。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，以寻找稀有的金属贫乏恒星，导致两个长期目标：(1)发现和分析整个银河系和矮星系中的金属贫乏恒星-银河系和附近卫星中的金属贫乏恒星的研究显示了化学丰度模式的不同，这是由于一系列（简并）星系和恒星建模假设。需要更大的统计样本来打破这些简并并绘制出金属贫乏的银河系。(2)了解重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，尽管在中子星合并中发现了r过程核合成，作为普遍存在的r过程位点的补充，这是一个重大突破。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。该研究计划将使用双子座天文台的GRACES和即将到来的GHOST光谱仪对金属贫乏恒星进行高分辨率（R bbb50,000）光谱；GHOST对于低于450 nm的r-过程元素谱线尤其必要。该计划还将使用即将到来的WEAVE光谱调查中金属贫乏恒星（~3000个目标）的光谱。因此，这是一个激动人心的时刻，可以在各种星系环境（星系凸起、星系平面、球状星团、星系流和矮星系）中发现和分析大量缺乏金属的恒星。我的研究项目的影响将是更好地了解重元素的起源和金属贫乏星系的组装历史，从而改进星系和恒星建模。该项目为HQP提供了观测和理论天体物理学方面的培训机会，以及开发新的数据分析方法（例如，机器学习算法）和参与仪器开发（例如，GHOST的科学验证）的独特机会，从而为未来的加拿大设施（例如，TMT， MSE或同等设备）做准备。

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).