title: The Impact of Metallicity on the Rate of Type Ia Supernovae
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Introduction {#section:introduction}
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The end result of the evolution of stars that produce white dwarfs is often a Type Ia supernova explosion, through a single-degenerate channel (e.g., @Whelan73), double-degenerate channel (e.g., @Iben:1984iz [@Webbink:1984ti]), or both. Since stellar evolution is obviously affected by metallicity, there is no a priori reason why the rate of SNe Ia should not significantly depend on metallicity. From a theoretical standpoint, a preference for high metallicity was proposed by @Kobayashi:1998ii, whose single-degenerate model required a minimum metallicity of $\sim 0.1\,Z_\odot$ in order to produce Type Ia SNe. A similar preference for higher metallicity was seen in the single degenerate models of @Langer:2000fs. However, the strong predictions offered by these models, such as no Type Ia SNe in dwarf galaxies and the outskirts of spirals, were not confirmed observationally (e.g., @Prieto). The viability of the single-degenerate channel to produce the majority of Type Ia SNe has been debated from both observational (e.g., @Leonard:2007nh [@Simon:2009hk; @Gilfanov:2010ip]) and theoretical viewpoints [@Ruiter:2009dk; @Kasen; @Hachisu], while simulations of double-degenerate mergers still do not yield normal SNe Ia [@Pakmor:2009yx; @Fryer:2010jx].

From the viewpoint of stellar evolution, we expect an 