Zusammenfassung
We describe a new method for adding a prescribed amount of kinetic energy to
simulated gas modeled on a cartesian grid by directly altering grid cells' mass
and velocity in a distributed fashion. The method is explored in the context of
supernova feedback in high-resolution hydrodynamic simulations of galaxy
formation. In idealized tests at varying background densities and resolutions,
we show convergence in behavior between models with different initial kinetic
energy fractions at low densities and/or at high resolutions. We find that in
high density media ($\gtrsim$ 50 cm$^-3$) with coarse resolution ($4$
pc per cell), results are sensitive to the initial fraction of kinetic energy
due to the early rapid cooling of thermal energy. We describe and test a
resolution dependent scheme for adjusting this fraction that approximately
replicates our high-resolution tests. We apply the method to a prompt supernova
feedback model, meant to mimic Type II supernovae, in a cosmological simulation
of a $10^9$ Msun halo. We find that depositing small amounts of supernova
energy in kinetic form (as little as 1%) has a dramatic impact on the evolution
of the system, resulting in an order of magnitude suppression of stellar mass.
We discuss the distribution of stellar metallicities in the resulting system
and find that while the mean metallicity is much more consistent with
observations than in previous models, significant discrepancies remain that are
likely due to our simplistic assumptions for the source of stellar feedback
that neglect contributions from Type Ia supernovae and stellar winds.
Nutzer