Physical asymmetries in disk galaxies are normal. Over 50% of "normal" spiral galaxies in the field have asymmetric neutral Hydrogen (HI) line profiles and distributions, while optical asymmetries are seen in some 40% of spiral galaxies. The physical processes responsible for asymmetries in galaxies are thought to be accretion and interaction. However, direct evidence of accretion is scant and the physical effects of interactions on galaxies, particularly weak interactions, have yet to be quantified. The research to be carried out is a combination of studies of the distribution and kinematics of HI around galaxies in a variety of environments and optical wavelength studies of the morphology and star formation histories of individual galaxies. This is being done to measure the impact of accretion and interaction on galaxy evolution.
The results from this project will be: 1) a measure of the current accretion rate and its implications for models of galaxy formation and evolution; 2) an estimate of the impact of accretion on the physical properties of galaxies; 3) a determination of the role of accretion and interaction in shaping the pronounced asymmetries of barred Magellanic spirals; and 4) a description of the evolution of the gaseous content of loose groups of galaxies to trace how the roles of accretion and interaction change as the environment in which the galaxies reside changes.
A detailed and thorough mapping of the HI content of galaxies and their environments is at the heart of the project. The analysis of the HI data will yield a measure of the amount of gas around individual galaxies that is being, or could be accreted, as well as information on the magnitude of any interactions in which the galaxy is participating. The response of the galaxy to such external perturbations will be derived from data from optical studies of its star formation and morphology using the WIYN telescope.
One aspect of the educational component that will be carried out concurrently with the research will be the development of a new course. The course will be designed to reach across disciplines and to encourage collaborative learning. The goal of the course is to teach the chemical history of minerals, beginning with nucleosynthesis, and ending with the incorporation of those minerals in the Earth's interior.
The bulk of the educational component centers on outreach in three major ways. The first is a continuation and expansion of an extremely popular and successful program called "Universe in the Park" in which astronomers visit state parks throughout Wisconsin during the summer and fall camping seasons. The second outreach component will be to use the University's "Space Place" as a science museum and resource center for area science teachers. This activity will entail the development of a series of interactive exhibits to engage the numerous school groups that visit Space Place throughout the year. Another aspect of this program will be to continue and enhance a series of teacher workshops hosted at Space Place. The third component of the outreach program is to develop a long-term relationship between the principal investigator and students at area schools, particularly those with large populations of minority students, through regular visits to science classrooms throughout the academic year.
