Chemodynamical simulations with variable IMF

Using self-consistent chemodynamical simulations including star formation, supernova feedback, and chemical enrichment, I show the dependence of cosmic star formation and chemical enrichment histories on the initial mass function (IMF). The effects of Pop-III IMF can be only seen in the elemental abundance ratios at z > ∼ 4 or [Fe/H] < ∼ −2. The preferable IMF has a flatter slope in the case of high star formation rate (SFR) and smaller upper-mass (∼ 20M⊙) in the case of low SFR, which is consistent with the observed elemental abundances of dwarf spheroidal galaxies. However, the [α/Fe] problem of elliptical galaxies may require other solutions.