SN-driven mechanism of cusp-core transformation: an appraisal
  We present and test an effective model for N -body simulations that aims at
mimicking the impact of supernova (SN) feedback on the dark matter (DM)
distribution of isolated halos hosting dwarf galaxies. Although the model is
physically decoupled from the cosmological history of both the DM halo and the
dwarf galaxy, it allows us to study the impact of different macroscopic
parameters such as galaxy concentration, feedback energy and energy injection
time in the process of SN-driven core formation in a physically clear way.
Using our effective model in a suite of N-body simulations of an isolated halo
with different SN feedback parameters, we find that whether or not a DM core
forms is determined by the total amount of SN feedback energy that is
transferred to the DM particles. At a fixed injected energy, the amount of
transferred energy is bigger - and the size of the DM core is larger - the
faster the energy injection occurs and the more compact the dwarf galaxy is.
Analyzing the orbital evolution of kinematic tracers, we demonstrate that a
core forms through SN feedback only if the energy injection is impulsive
relative to the dynamical timescale of particles in the inner halo. However,
there is no fundamental link between the total amount of injected energy and
the injection rate. Consequently, the presence of signatures of impulsive
changes of the gravitational potential is not a sufficient condition for
dwarf-size halos to have cored density profiles.
