Low-metallicity inhibition of type Ia supernovae and galactic and cosmic chemical evolution
We introduce a metallicity dependence of the Type Ia supernova (SN Ia) rate into the Galactic and cosmic chemical evolution models. In our SN Ia progenitor scenario, the accreting white dwarf (WD) blows a strong wind to reach the Chandrasekhar mass limit. If the iron abundance of the progenitors is as low as [Fe/H] less than or similar to -1, then the wind is too weak for SNe Ia to occur. Our model successfully reproduces the observed chemical evolution in the solar neighborhood. We make the following predictions that can test this metallicity effect: (1) SNe Ia are not found in the low iron abundance environments such as dwarf galaxies and the outskirts of spirals. (2) The cosmic SN Ia rate drops at z similar to 1-2, because of the low iron abundance, which can be observed with the Next Generation Space Telescope. At z greater than or similar to 1-2, SNe Ia can be found only in the environments where the timescale of metal enrichment is sufficiently short as in starburst galaxies and elliptical galaxies. The low-metallicity inhibition of SNe Ia can shed new light on the following issues: (1) The limited metallicity range of the SN Ia progenitors would imply that "evolution effects" are relatively small for the use of high-redshift SNe Ia to determine the cosmological parameters. (2) WDs of halo populations are poor producers of SNe Ia, so that the WD contribution to the halo mass is not constrained from the iron abundance in the halo. (3) The abundance patterns of globular clusters and field stars in the Galactic halo lack of SN Ia signatures in spite of their age difference of several Gyr, which can be explained by the low-metallicity inhibition of SNe Ia. (4) It could also explain why the SN Ia contamination is not seen in the damped Ly alpha systems over a wide range of redshift.