but also of heating.

Feedback processes like the return of mass to the interstellar medium, supernova heating and chemical enrichment were all taken into account. The return of mass to the interstellar medium was computed by assuming that the initial mass function (IMF) of stars with metallicities $[Z/H] < −2.0$ is of the form $\zeta(m) \propto m^{-2}$ while stars more metal-rich are formed with a Salpeter IMF, e.g., $\zeta(m) \propto m^{-2.35}$. Stars in the mass range $40-80~ M_\odot$ leave a $10~ M_\odot$ black hole as a remnant, whereas a $1.4~ M_\odot$ neutron star is left if progenitors are in the mass range $9-40 M_\odot$ or a white dwarf remnant otherwise. The mass lost by the ”stellar particle" is redistributed according to the SPH kernel among the gas particle neighbors and velocities are adjusted in order to conserve the total momentum in the cell. Moreover, the removed gas (except that ejected by supernovae, as discussed below) keeps its original chemical composition, contributing to the chemical budget of the medium. In fact, AGB stars, planetary nebulae and WR stars enrich the medium in He, C, N, but these contributions are not taken into account in the present version of the code.

Supernova 