Effects of Symmetry Energy on the Equation of State for Simulations of Core-collapse Supernovae and Neutron-star Mergers

Abstract

We construct a new equation of state (EOS) for numerical simulations of core-collapse supernovae and neutron-star mergers based on an extended relativistic mean-field model with a small symmetry energy slope L, which is compatible with both experimental nuclear data and recent observations of neutron stars. The new EOS table (EOS4) based on the extended TM1 (TM1e) model with L = 40 MeV is designed in the same tabular form and compared with the commonly used Shen EOS (EOS2) based on the original TM1 model with L = 110.8 MeV. This is convenient and useful for performing numerical simulations and examining the influences of symmetry energy and its density dependence on astrophysical phenomena. In comparison with the TM1 model used in EOS2, the TM1e model provides a similar maximum neutron-star mass but smaller radius and tidal deformability for a 1.4M ⊙ neutron star, which is more consistent with current constraints. By comparing the phase diagram and thermodynamic quantities between EOS4 and EOS2, it is found that the TM1e model predicts relatively larger region of nonuniform matter and softer EOS for neutron-rich matter. Significant differences between EOS4 and EOS2 are observed in the case with low proton fraction, while the properties of symmetric matter remain unchanged.

Systematic study on the quark-hadron mixed phase in compact stars

“…In this work, we investigate systematically the possible hadron-quark deconfinement phase transition in dense stellar matter and its influence on compact star structures. For the hadronic phase, we adopt in total ten different EOSs, i.e., eight nuclear EOSs (TM1e [66], TM1 [64], PKDD [74], TW99 [43], DDME2 [75], DD2 [76], VM [49], APR [48]) and two hyperonic EOSs (TM1Λ [70] and VMΛ [83]), which are predicted by relativistic-mean-field model [47] and variational method with realistic baryon interactions [48,49]. For the quark phase, we adopt 46 EOSs predicted by equivparticle model [50][51][52], perturbation model [44,53,54], and NJL model with vector interactions [55,56].…”

“…This gives Shen EOS4 by adopting the effective interaction TM1e [66]. To further include the contribution of Λ hyperons, in Eq.…”

“…[94][95][96], which account for the crusts of neutron stars. For the cases of TM1, TM1Λ, TM1e, VM, and VMΛ, the crust EOSs were previously obtained, i.e., Shen EOSs [65,66] and VM EOSs [49,83]. However, instead of using those EOSs, we still adopt the crust EOSs presented in Refs.…”

Equation of state and neutrino transfer in supernovae and neutron stars

“…where the standard notation is used. The meson-nucleon coupling constants (g σ , g ω , g ρ ), meson self-coupling constants (g 2 , g 3 , c 3 ), and ω-ρ coupling constant ( v ) as well as the meson masses (m σ , m ω , m ρ ) are the parameter of the theory (See [53,81] for details).…”

“…The data table of the revised Shen EOS with TM1e has been constructed in the same framework and format as Shen EOS with TM1 and is publicly available [81]. The two sets of EOS with TM1 and TM1e can be used to explore the influ-Fig.…”