Some Stars Fade Quietly: Varied Supernova Explosion Outcomes and Their Effects on the Multiphase Interstellar Medium

Abstract We present results from galaxy evolution simulations with a multiphase interstellar medium (ISM), a mass resolution of 4 M ⊙ , and a spatial resolution of 0.5 pc. These simulations include a resolved stellar stellar feedback model. Our fiducial run WLM-fid adopts 10 51 erg for the supernova (SN) energy. Among the remaining seven simulations, there are two runs where we vary this number by fixing the energy at 10 50 erg and 10 52 erg (WLM-1e50 and WLM-1e52). Additionally, we carry out one run with variable SN-energy (WLM-variable) and run two simulations where only 10% or 60% of stars explode as SNe with 10 51 erg, while the remaining stars do not explode (WLM-60prob and WLM-10prob). We find that the variation in the SN energy, has only minor effects: the star formation rate changes by roughly a factor of 2 compared to WLM-fid, and the strength of the galactic outflows in mass and energy is reduced by 30%, with typical values of η m ∼ 0.1 and η e ∼ 0.05 (at a height of 3 kpc after the hot wind is fully decoupled from the galactic ISM). In contrast, the increase and decrease in the canonical SN-energy have a clear impact on the phase structure, with loading factors that are at least 10 times lower/higher and a clear change in the phase structure (the energy loading is normalized self-consistently to the initial mass function averaged explosion energy). We conclude that these modulations are driven not by the minor change in SN-energy but rather by the likelihood of whether or not an event occurs when variable SN energies are applied.