Galaxy Evolution: Tidal Remnants, Outflows, and Inflows

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Dr. Kathleen Barger is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Notre Dame. One of the most pressing problems in galaxy formation concerns how gas accretion and feedback influence the evolution of galaxies. Galaxy evolution is regulated by the ability of galaxies to accrete and retain gas to continue star formation, but how does matter cycle in and out of galaxies? Recent theoretical studies suggest that predominantly ionized material may infall onto galaxies through intergalactic filaments, but it is unclear whether the gas will evaporate in the halo before reaching the galactic disk. In contrast, feedback from massive stars expels gas and quenches star formation by heating and ionizing the gas. To understand outflow and inflow processes in galaxies at greater distances, the fellow in this project will study them in the local Universe, where they can be studied in detail.To decipher the flows in the circumgalactic gas of the Milky Way, the fellow will combine Wisconsin H-Alpha Mapper (WHAM) optical and Hubble Space Telescope ultraviolet spectroscopic observations of the Large Magellanic Cloud (LMC) outflow and Magellanic Stream to test if dwarf galaxies can sustain massive galaxy star formation and to test the origin of the gaseous structures feeding galaxies. The Magellanic Clouds are nearby enough to exploit the power of absorption- and emission-line spectroscopy, allowing investigators to measure the density, temperature, metallicity, kinematics, and morphologies of the diffuse circumgalactic gas. Through these observations the fellow will investigate the LMC stellar outflows and the Magellanic Stream to determine their basic physical properties, the source of their ionization, their extent and morphology, and their fate. Establishing a new perpective of the gaseous flows in our own Galactic environment will provide a firmer basis to understand the implications of gas detected far from galaxies throughout the Universe.The broader impacts of this project include a significant educational component. The fellow will create a Professional Resource Development program for the Physics Department at the University of Notre Dame. This program will consist of an annual professional development seminar along with complementary workshops. The Professional Resource Development seminar will include topics on traditional academic and alternative career paths, networking, and job applications in conjunction with members of the Professional Development Committee at Notre Dame, whose membership includes the Kaneb Center for Teaching and Learning, Writing Center, Graduate School, English for Academic Purposes, Reilly Center for Science, among others. Each summer this program will include three workshops on Curriculum Vitae, research statements, and cover letters and will stress the importance of strong communication skills and tailoring documents to different audiences. The fellow's program in the Physics Department will serve as a model for similar professional development resources applicable across the College of Science.