On the Importance of the Equation of State for the Neutrino-Driven Supernova Explosion Mechanism. (arXiv:1206.6101v1 [astro-ph.HE])

On the Importance of the Equation of State for the Neutrino-Driven Supernova Explosion Mechanism. (arXiv:1206.6101v1 [astro-ph.HE]):
We present results from spherically symmetric (1D) and axially symmetric (2D)
core-collapse supernova simulations. Our model is based on neutrino radiation
hydrodynamics, including spectral neutrino transport. We apply the equations of
state (EOS) from Lattimer & Swesty (LS) and Shen et al. (SHEN), and explore the
differences obtained during the post-bounce phase prior to the possible onset
of a neutrino-driven explosion. We confirm that in 1D simulations
neutrino-driven explosions cannot be obtained for any of the employed EOS. In
2D, EOS induced structural differences lead to a more efficient neutrino
heating, in particular for LS in comparison to the simulations that use SHEN.
For simulations of the 15 M_sun progenitor with LS under investigation, it
results in a continuous expansion of the stalled bounce shock to increasingly
larger radii, which is absent using SHEN. Simulations of a 11.2 M_sun
progenitor result in neutrino-driven explosions for all EOS under
investigation, however slightly more powerful for LS than for SHEN and also
slightly delayed for the latter. The generally more efficient neutrino heating
using LS can be related to the higher electron antineutrino luminosity and the
more mass enclosed inside the gain region. It also leads to the development of
an aspherical downflow of material from large radii to the central protoneutron
star surface for LS, which in turn supplies continuously energy to the
protoneutron star. Moreover, we investigate several additional indicators of
the explosion, e.g., the amplitude of the standing-accretion shock instability
mode, the mass weighted average entropy in the gain region, the protoneutron
star radius, the antesonic condition, and the ratio of advection and heating
timescales.