The H3 Spectroscopic Survey and the Origin of the Galaxy

H3 光谱巡天和银河系的起源

• 批准号: 2107253
• 负责人: Charles Conroy
• 金额: $ 57万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2107253&HistoricalAwards=false
• 关键词: H3; Spectroscopic; Survey; Origin; Galaxy

A main component of our Milky Way galaxy is its stellar halo, a spherical distribution of stars extending 10 times further than the stellar disk. Galaxy formation theories predict that our Milky Way's stellar halo was formed from "shredding" of smaller galaxies. However, this theory has not yet been confirmed observationally. In this project the investigators will measure the basic stellar properties (velocities, distances, and "chemistry") of 300,000 stars in the stellar halo. With these data they will provide a full inventory of the building blocks that formed our stellar halo. Stellar ages, which are measured as part of this project, will be used to deduce the timeline of star formation and galaxy merger events. Finally, the investigators will use these observations to predict the effect of the Milky Way's largest satellite companion, the Large Magellanic Cloud, on the stellar halo. Such observations may provide unique insight into the nature of dark matter and gravity. Educationally, this project will support a graduate student who will be trained on the analysis of stellar spectra and the application of dynamical models to the Galaxy. The project will also support the training of summer undergraduates from under-represented backgrounds as part of the Banneker Institute. The Banneker Institute has a summer program aimed at developing students’ research skills and social justice education.The “Hectochelle in the Halo at High Resolution” (H3) Survey will deliver high resolution spectra of stars in high Galactic latitude fields in the Northern hemisphere to measure radial velocities, spectrophotometric distances, [Fe/H], and [alpha/Fe] relative abundances. Determining these parameters will be used to explain the origin of structures in phase plus chemistry space. These observations will enable detailed constraints on the assembly history of the Galaxy, measurements of the mass profile of the outer Galaxy, the origin of the in-situ stellar halo, and will be sensitive to a variety of interesting, rare populations such as chemically peculiar stars and high velocity stars.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.

我们银河系的一个主要组成部分是它的恒星晕，这是一种比恒星盘还要远10倍的恒星分布，银河系形成理论预测我们银河系的恒星晕是由较小的星系“粉碎”形成的。这一理论尚未得到观测证实。在这个项目中，研究人员将利用这些来测量恒星晕中 300,000 颗恒星的基本恒星特性（速度、距离和“化学”）。他们将提供形成恒星光环的组成部分的完整清单，作为该项目的一部分进行测量，这些数据将用于推断恒星形成和星系合并事件的时间表。这些观测预测了银河系最大的卫星伴星大麦哲伦星云对恒星晕的影响，这些观测可能会为暗物质和引力的本质提供独特的见解，该项目将为研究生提供支持。接受恒星分析培训作为班纳克研究所的一部分，该项目还将支持对来自代表性不足的背景的暑期本科生的培训，该项目旨在培养学生的研究技能和社会正义。 “高分辨率光晕中的 Hectochelle”（H3）巡天将提供北半球高银河纬度区域恒星的高分辨率光谱，以测量径向速度、分光光度距离、[Fe/H] 和 [α/Fe] 相对丰度将用于解释相加化学空间中的结构起源，这些观测结果将能够对星系的组装历史、测量进行详细限制。外星系的质量分布、原位恒星晕的起源，并且将对各种有趣的稀有群体敏感，例如化学上奇特的恒星和高速恒星。该奖项反映了 NSF 的法定使命，并已通过评估认为值得支持利用基金会的智力优势和更广泛的影响审查标准。

项目成果

Distant Echoes of the Milky Way’s Last Major Merger

• DOI: 10.3847/1538-4357/accf13
• 发表时间: 2022-12
• 期刊: The Astrophysical Journal
• 作者: V. Chandra;R. Naidu;C. Conroy;A. Ji;H. Rix;A. Bonaca;P. Cargile;Jiwon Jesse Han;Benjamin D. Johnson;Y. Ting 丁;T. Woody;D. Zaritsky

Wide binaries from the H3 survey: the thick disc and halo have similar wide binary fractions

H3 巡天的宽双星：厚盘和光环具有相似的宽双星分数

• DOI: 10.1093/mnras/stac650
• 发表时间: 2022
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Hwang, Hsiang-Chih;Ting, Yuan-Sen;Conroy, Charlie;Zakamska, Nadia L.;El-Badry, Kareem;Cargile, Phillip;Zaritsky, Dennis;Chandra, Vedant;Han, Jiwon Jesse;Speagle, Joshua S.
• 通讯作者: Speagle, Joshua S.

The Stellar Halo of the Galaxy is Tilted and Doubly Broken

• DOI: 10.3847/1538-3881/ac97e9
• 发表时间: 2022-08
• 期刊: The Astronomical Journal
• 作者: Jiwon Jesse Han;C. Conroy;Benjamin D. Johnson;J. Speagle 沈;A. Bonaca;V. Chandra;R. Naidu;Y. Ting