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

点击翻译按钮获取中文摘要

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.