RUI: The Survey of HI in Extremely Low-mass Dwarfs (SHIELD)

星系最初是如何形成的，以及它们在一生中是如何变化的，这是天体物理学中最不为人所知的问题。 许多项目都集中在解开这些谜团。 该项目旨在描述极低质量矮星系的气体和恒星成分，这对于我们理解气体在浅层引力势威尔斯中转化为恒星的过程至关重要。 该项目将对从最近的ALCAFA（阿雷西博遗产快速ALFA [阿雷西博L波段馈源阵列]）目录中选出的12个极低质量星系进行全面的多波长调查。 该项目调查的基石是使用最近扩大的Jansky超大阵列（JVLA）对所有12个星系进行深原子氢（HI）光谱线成像，JVLA是NSF资助的设施。 一套丰富的配套观测设施，（包括GALEX卫星、哈勃太空望远镜、斯皮策太空望远镜、WIYN天文台和基特峰国家天文台）将允许探索对我们理解星系演化至关重要的多个科学主题。具体而言，首席研究员（PI）已着手解决以下问题：（1）小晕、质量很低的矮星和质量更大的系统之间有什么性质的变化？ (2)在低质量矮星中，重子质量占质量的比例是多少？ (3)在质量很低的星系中，星星形成过程的特征是否不同？在教育方面，PI将让本科生参与前沿研究。 这种教育和培训将针对Macalester学院的三个学生群体。 第一个目标人群是参加观测天文学课程的高级物理学和天文学专业学生;这些学生将通过参与该项目获得射电天文学技术方面的严格理论背景和基于研究的学习。 第二个目标人群是暑期研究助理，通常是一个正在上升的大三或大四物理和天文学专业的学生，他们将致力于为这个项目获得的数据。 这些为期10周的预约使学生能够深入沉浸在天体物理学研究中，并为研究生学习的挑战做好准备。 第三个目标人群是学士后研究助理。 这种越来越受欢迎的职业轨道允许学生在完成本科学业后但进入研究生院之前花一年时间从事全职研究。 “后bac”获得了独特的教育经验，同时确保科学计划的前进。 各级本科生将通过专题会议和天体物理学文献出版向社会传播科学成果。

Precisely how galaxies initially form and how they change throughout their lifetimes are among the least understood problems in astrophysics. Many projects are centered on unraveling these mysteries. This project aims to characterize the gaseous and stellar components of extremely low-mass dwarf galaxies, which is critical for our understanding of the processes by which gas is converted into stars in shallow gravitational potential wells. The project will conduct a comprehensive, multi-wavelength survey of 12 extremely low-mass galaxies selected from the recent ALFALFA (Arecibo Legacy Fast ALFA [Arecibo L-band Feed Array]) catalogue. The cornerstone of this project's survey is deep atomic hydrogen (HI) spectral line imaging of all 12 galaxies with the recently expanded Jansky Very Large Array (JVLA), an NSF-funded facility. A rich suite of supporting observations with various facilities (including the GALEX satellite, the Hubble Space Telescope, the Spitzer Space Telescope, the WIYN observatories, and the Kitt Peak National Observatory) will allow the exploration of multiple science themes that are critical to our understanding of galaxy evolution.Specifically, the principal investigator (PI) has set out to address the following questions: (1) What properties change between mini-halos, very low-mass dwarfs, and more massive systems? (2) What fraction of the mass in low-mass dwarfs is baryonic? (3) Is the character of the star formation process different in very low-mass galaxies?Educationally, the PI will engage undergraduate students in forefront research. This education and training will target three student populations at Macalester College. The first target population is the upper-level physics and astronomy major enrolled in the Observational Astronomy course; these students will obtain a rigorous theoretical background in radio astronomy techniques and exposure to research-based learning via their involvement with this project. The second target population is the summer research associate, typically a rising junior or senior physics and astronomy major who will work on the data acquired for this project. These 10-week appointments allow students to obtain a deep immersion in astrophysical research and prepare them for the challenges of graduate study. The third target population is the post-baccalaureate research associate. This increasingly popular career track allows students to spend a year engaged in full-time research after the completion of their undergraduate studies but prior to entering graduate school. The "post-bac" attains a unique educational experience while assuring the forward progress of the science program. Undergraduate students at all levels will disseminate science results to the community by presenting at topical meetings and by publishing in the astrophysical literature.