Low-Metallicity Inhibition of Type Ia Supernovae and Galactic and Cosmic Chemical Evolution

We introduce a metallicity dependence of Type Ia supernova (SN Ia) rate intothe Galactic and cosmic chemical evolution models. In our SN Ia progenitorscenario, the accreting white dwarf (WD) blows a strong wind to reach theChandrasekhar mass limit. If the iron abundance of the progenitors is as low as[Fe/H] < -1, then the wind is too weak for SNe Ia to occur. Our modelsuccessfully reproduces the observed chemical evolution in the solarneighborhood. We make the following predictions which can test this metallicityeffect: 1) SNe Ia are not found in the low-iron abundance environments such asdwarf galaxies and the outskirts of spirals. 2) The cosmic SN Ia rate drops atz \sim 1-2 due to the low-iron abundance, which can be observed with the NextGeneration Space Telescope. At z > 1-2, SNe Ia can be found only in theenvironments where the timescale of metal enrichment is sufficiently short asin starburst galaxies and ellipticals. The low-metallicity inhibition of SNe Ia can shed new light on the followingissues: 1) The limited metallicity range of the SN Ia progenitors would implythat ``evolution effects'' are relatively small for the use of high redshiftSNe Ia to determine the cosmological parameters. 2) WDs of halo populations arepoor producers of SNe Ia, so that the WD contribution to the halo mass is notconstrained from the iron abundance in the halo. 3) The abundance patterns ofglobular clusters and field stars in the Galactic halo lack of SN Ia signaturesin spite of their age difference of several Gyrs, which can be explained by thelow-metallicity inhibition of SNe Ia. 4) It could also explain why the SN Iacontamination is not seen in the damped Ly\alpha systems for over a wide rangeof redshift.Comment: 6 pages LaTeX, 4 PostScript figures, to appear in ApJ Letter