A Pioneering Test of Stellar Population Complexity Outside the Milky Way

银河系外恒星种群复杂性的开创性测试

• 批准号: 1911129
• 负责人: Gail Zasowski
• 金额: $ 27.66万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1911129&HistoricalAwards=false
• 关键词: Pioneering; Test; Stellar; Population; Complexity

The investigator will test the uniqueness of the Milky Way Galaxy's chemical composition. Their goal is understanding how other galaxies change with time, based on observations of stars in the Milky Way (MW). Observations of individual stars in the MW show that the chemistry and the motions of stars are related. These relationships have guided our understanding of how other galaxies change over time and chemically enrich the Universe. Studying the changes in other galaxies over time is extremely difficult. The project team will pioneer new techniques for testing if these patterns occur in the Andromeda Galaxy, the nearest galaxy that is similar to the MW. These measurements will provide insight into that galaxy's history, the uniqueness of the MW, and the usefulness of these systems for tracing how galaxies have grown since the Big Bang. To analyze existing high-resolution, near-infrared (NIR) spectra spanning a large fraction of Andromeda's bulge and disk, the project team will first construct a library of Simple Stellar Population (SSP) models based on theoretical isochrones and nearly 400,000 stellar spectra observations. The public release of this NIR library will fill a gap in the suite of SSP libraries available to the community.The project team will apply this library in two approaches to modeling the Andromeda integrated spectra, one using multi-component spectral fitting and one using machine learning with the SSP models as a training set. The comparison of the two approaches will be used to evaluate the consistency and robustness of the results in different parts of the galaxy. This program will constrain the presence of overlapping stellar populations in the inner regions of Andromeda with distinct dynamical and chemical properties that reflect their diverse histories, information that previously has been measured only in the MW. By revealing how similar Andromeda is to the MW in this important regard, this project will clarify to what extent our high-resolution picture of the MW can be applied to interpreting the unresolved starlight in other galaxies. More generally, these results will test theories of bulge and inner disk evolution and how that evolution is reflected in the constituent stellar populations.This program also supports efforts to promote scientific literacy to two important groups local to the project team: Utah's refugee community and visitors to Utah's national parks. The team will develop astronomy-themed workshops as part of an after-school program that helps middle- and high-school students from refugee families integrate into American classrooms and find social support. These workshops will promote positive perceptions of science and teach critical thinking, communication, and computational skills to students who face unique challenges to their education because of their family histories. The project also includes an extension of a high-impact outreach internship program to bring astronomy education to about 18,000 visitors at Bryce Canyon National Park. These two efforts will be linked by a visit of students from the refugee community to Bryce Canyon for an immersive outdoor experience under some of the US's darkest skies.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.

研究人员将测试银河系化学成分的独特性。 他们的目标是根据银河系（MW）对恒星的观察，了解其他星系如何随时间变化。 MW中单个恒星的观察表明，恒星的化学和运动是相关的。这些关系指导了我们对其他星系如何随时间变化并化学丰富宇宙的理解。随着时间的推移研究其他星系的变化非常困难。如果这些模式出现在仙女座银河系中，那么项目团队将开创新技术，以测试这些模式，这是与MW相似的最近的星系。这些测量结果将为您的银河历史，MW的独特性以及这些系统在追踪大爆炸以来的星系增长方面的实用性提供深入的了解。 为了分析现有的高分辨率，近红外（NIR）光谱，这些光谱涵盖了仙女座的凸起和磁盘的很大一部分，项目团队将首先建立一个基于理论等级和近400,000个恒星观测值的简单恒星种群（SSP）模型的库。该NIR库的公开发行将填补社区可用的SSP库中的空白。项目团队将以两种方法对Andromeda Integrated Spectra进行建模，其中一个使用多组件频谱拟合进行建模，并使用多种组件拟合，并使用机器学习将机器学习与SSP模型一起使用。两种方法的比较将用于评估银河系不同部分中结果的一致性和鲁棒性。该程序将限制仙女座内部区域中重叠的恒星种群的存在，具有不同的动力学和化学特性，这些特性反映了它们的各种历史，这是以前仅在MW中测量的信息。通过在这一重要方面揭示仙女座与MW的相似性，该项目将在多大程度上应用我们对MW的高分辨率图片在多大程度上可以应用于解释其他星系中未解决的星光。更笼统地，这些结果将测试凸起和内部磁盘进化的理论，以及如何在组成恒星种群中反映这种进化。该计划还支持为犹他州的难民社区和游客促进犹他州国家公园的两个重要团体来促进科学素养的努力。该团队将开展以天文学为主题的讲习班，作为一项课后计划的一部分，该课程帮助来自难民家庭的中学和高中生融入美国教室并寻求社会支持。这些讲习班将促进对科学的积极看法，并向由于家庭历史而面临独特的教育挑战的学生教授批判性思维，沟通和计算技能。该项目还包括一项高影响力外展实习计划的扩展，将天文学教育带到布莱斯峡谷国家公园的约18,000名游客。这两项努力将通过从难民社区到布莱斯峡谷的学生的访问来联系，以在美国一些最黑暗的天空下获得沉浸式的户外体验。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的审查标准来通过评估来通过评估来支持的。

项目成果

The Chemodynamics of the Stellar Populations in M31 from APOGEE Integrated-light Spectroscopy

• DOI: 10.3847/1538-4357/acd9a9
• 发表时间: 2023-04
• 期刊: The Astrophysical Journal
• 作者: B. J. Gibson;G. Zasowski;A. Seth;Aishwarya Ashok;Kameron Goold;T. Wainer;S. Hasselquist;J. Holtzman;J. Imig;D. Bizyaev;S. Majewski

The APOGEE Library of Infrared SSP Templates (A-LIST): High-resolution Simple Stellar Population Spectral Models in the H Band

• DOI: 10.3847/1538-3881/abd7f1
• 发表时间: 2020-12
• 期刊: The Astronomical Journal
• 作者: Aishwarya Ashok;G. Zasowski;A. Seth;S. Hasselquist;Galen J. Bergsten;Olivia R. Cooper;N. Boardman;D. Bizyaev;Sofia Meneses Goytia;D. A. García-Hernández;A. Roman-Lopes