THE MAGELLANIC STREAM: AGING, EXTENSION, AND ORBITS OF THE MAGELLANIC CLOUDS

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Under this award, Dr. Snezana Stanimirovic (University of Wisconsin - Madison) will carry out a study of how the hot Galactic atmosphere shapes the evolution of the Magellanic Stream (MS), a spectacular 100-degree long tail of neutral hydrogen (HI) trailing behind our closest neighbors, the Magellanic Clouds (MCs). This study is motivated by the recent discovery of a significant extension and of the complexity of MS gas. The complex small-scale structure of the MS gas suggests that dynamic interactions with the hot Galactic atmosphere are at work, especially at the northern extension of the MS. This area, in the form of several long filaments, is not explained by traditional models of the interactions between the Galaxy and the MCs. This project will obtain the most sensitive radio and optical observations to date of several regions along the MS with the Arecibo and Green Bank radio telescopes, and the Wisconsin-Indiana-Yale-National Optical Astronomy Observatory optical telescopes. The deep observations to be made will be used to search for morphological and spectral signatures of interactions between the Galactic atmosphere and the MS. The observations are essential samples to assess the prevalence and importance of different types of instabilities in the interface regions where these two media meet.This research will be the core topic of a Ph.D. dissertation at the University of Wisconsin-Madison and, therefore, represents a focused confluence of research and education. Another aspect of this project will be a collaboration with the staff at the Arecibo radio telescope to design and integrate a new method for the suppression of a strong radio interference signal caused by the Global Positioning System, which obliterates astronomical observations at a frequency of 1381 Megahertz. The developed method will be applicable to all radio telescopes world-wide. In addition, a new-generation education and research facility, based on three small radio telescopes, will be developed at the University of Wisconsin to integrate research with undergraduate classes.