NOAO >   Observing Info >   Approved Programs >   2009B-0176

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Proposal Information for 2009B-0176


PI: Peter Garnavich, University of Notre Dame, pgarnavi@miranda.phys.nd.edu
Address: Physics Department, 225 Nieuwland Hall, University of Notre Dame, Notre Dame, IN 46556, US

CoI: Robert Nichol, University of Portsmouth
CoI: Joseph Gallagher, Louisana State University
CoI: Masao Sako, University of Pennsylvania
CoI: Joshua Frieman, University of Chicago
CoI: David Cinabro, Wayne State University

Title: Social Insecurity: What Influences Stellar Death in Old Populations?

Abstract: We propose to directly measure the age and metallicity of the dominant stellar populations in E/S0 galaxies that have hosted type Ia supernovae discovered and studied during the SDSS-II Supernovae Survey. This experiment will test if the peak luminosity of a type Ia supernovae depends on the time since the progenitor was formed. Previous studies have used star-formation rate as a stand-in for age or host luminosity as a stand-in for metallicity and have focused on a "prompt" progenitor. But, recent direct measurements of age and metallicty in local E/S0 hosts appear to show a strong correlation between radioactive nickel production and age of the dominant population and suggests a gap between the prompt explosions and the long-lived progenitors. This study will also explore the influence of metallicity on the brightness of SNIa which may be a source of systematic error in cosmological measurements of dark energy. To accurately estimate the age/metallicity of E/S0 galaxies at z=0.2 requires good signal-to-noise ratio absorption line spectra achievable only with an 8-m class telescope.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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