All Figures

	Figure 1: The ratio of the angle-averaged ion-ion correlation factor as calculated with the fitting formula of Horowitz (1997) (see Fig. 9 in Bruenn & Mezzacappa 1997) relative to the one obtained from the prescription provided by Itoh et al. (2004, see their Fig. 2) as a function of the variable for different values of the dimensionless parameter .
Open with DEXTER


In the text

Figure 2: Composition as a function of density at the center ( top) and at an enclosed mass of 0.5 ( bottom) for the evolution during core collapse with the EoSs of Lattimer & Swesty (1991, left) and Shen et al. (1998a,b, right). The plots show the evolution of the number fractions Y for free neutrons, protons, -particles, and the representative heavy nucleus until shock formation. The results were obtained with ion-ion screening treated according to case "EoS_ion_Itoh'' (see text).

Open with DEXTER


In the text

Figure 3: Central electron fraction and lepton fraction as functions of central density for core collapse calculations with the EoS of Shen et al. (1998a,b). Model Shen_ion_off does not include the effects of ion-ion correlations, Model Shen_ion_Hor uses the description of ion screening according to Horowitz (1997), Model Shen_ion_Itoh employs the Itoh et al. (2004) treatment for a one-component plasma, and Model Shen_ion_mix their treatment of ionic mixtures.

Open with DEXTER


In the text

	Figure 4: Same as Fig. 3 but for the central (matter) entropy s.
Open with DEXTER


In the text

	Figure 5: Gas entropy vs. enclosed mass at the moment of shock formation in the models of Figs. 3 and 4. The shock formation is defined by the instant when the entropy in the core first reaches a value of 3 per nucleon.
Open with DEXTER


In the text

	Figure 6: Spectra of neutrino energy density (solid line) and energy flux (dashed) for Model Shen_ion_off ( left) and Model Shen_ion_Hor ( right), when a density of 1012 g cm-3 is reached at an enclosed mass of 0.3.
Open with DEXTER


In the text

	Figure 7: Profiles of electron fraction , lepton fraction ( left), and (gas) entropy s ( right) versus enclosed mass for Models Shen_ion_off (dotted), Shen_ion_Hor (solid), Shen_ion_Itoh (dashed), and Shen_ion_mix (dash-dotted) at the time when the central density has reached a value of 1014 g cm-3.
Open with DEXTER


In the text

Figure 8: The energy source term for neutrino-electron scattering for densities of a) 1011 g cm-3 and b) 1012 g cm-3at the stellar center in the collapse models with the Shen et al. (1998a,b) EoS. Negative values mean that neutrino energy is "absorbed'' (net scattering out of the corresponding energy bin), and positive values mean "emission'' of neutrino energy (i.e., net scattering of neutrinos into the energy bin).

Open with DEXTER


In the text

Figure 9: The optical depth for energy exchange between neutrinos and stellar plasma as a function of the neutrino energy at the center of the iron core for densities of a) 1011 g cm-3, b) 1012 g  cm-3, c) 1013 g cm-3, and d) 1014 g  cm-3. The results were taken from collapse calculations with the Shen et al. (1998a,b) EoS. The left panels show enlargements of the low-energy window where ion-ion correlations have the largest effect.

Open with DEXTER


In the text

Figure 10: The cross-section suppression factor for neutrino scattering off heavy nuclei (bold lines) as function of neutrino energy at the center of the iron core for densities of: a) 1011 g cm-3, b) 1012 g cm-3, c) 1013 g cm-3, and d) 1014 g cm-3. The results are taken from collapse simulations with the Shen et al. (1998a,b) EoS. Also plotted (thin solid lines with crosses) are the local spectra of the neutrino energy density (normalized to the spectral maximum), which are practically identical for all simulations.

Open with DEXTER


In the text