Probing the Evolution of Galaxies and Clusters with Planetary Nebulae

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AST-0071238CiardulloThe goals of this project are to use redshifted [O III]-5007 filters to imagie and identify planetary nebulae (PNe) associated with the nearby galaxies: M31, NGC 720, 1399, 4406, 4472, and 4636 and the intracluster stars (associated with PNe) found in nearby galaxy clusters. These PNe will then be studied spectroscopically (using the Hobby-Eberly Telescope at McDonald Observatory) to obtain their kinematics and abundances which can be used to study the distances, gravitational potential, and evolutionary history of their surroundings.Stars like the Sun do not live forever. Eventually, they expand to tremendous size, throw off their atmosphere, and die. In the process, the stars become "planetary nebulae" (PN), beautiful formations of glowing gas that are lit up by the stars' last embers. When viewed at great distances, one cannot see the details of these nebulae. However one can use the PN's distinctive emission to investigate a host of problems in astrophysics and cosmology. Specifically, PN can be use to a) better define the extragalactic distance scale and Hubble Constant, b) study post-asymptotic giant branch evolution in old stellar populations, c) probe the stellar motions dark matter content of elliptical galaxies, d) measure the chemical composition and chemical evolution of nearby galaxies, and e) study the structure and evolution of galaxy clusters via their intracluster stars. We are proposing to continue our successful program of using planetary nebulae to probe these topics. Our immediate goals will be to measure the chemical and star formation history of our nearest spiral galaxy, M31, explore the mass distributions of the large elliptical galaxies of Virgo, and learn about the formation and dynamical evolution of galaxy clusters. Our observations will lead directly to improved constraints on the formation and evolution of galaxies, and the nature of dark matter halos.***