Chemical evolution using smooth particle hydrodynamical simulations. I - Implementation, tests and first results

We develop a model to implement metal enrichment in a cosmological context based on the hydrodynamical code AP3MSPH described by Tissera et al. (1997). The star formation model is based on the Schmidt law, and has been modified in order to describe the transformation of gas into stars in more detail. The enrichment of the interstellar medium resulting from Type I and II supernovae explosions is taken into account by assuming a Salpeter initial mass function and different nucleosynthesis models. The various chemical elements are mixed within the gaseous medium according to the smooth particle hydrodynamics technique. We present tests of the code that assess the effects of resolution and model parameters on the results. We show that the main effect of low numerical resolution is to produce a more effective mixing of elements, resulting in abundance relations with less dispersion. (Author)