Constraints on the nuclear symmetry energy via asteroseismology

We examine the fundamental torsional oscillations of the crust in the neutron star. Especially, we focus on the crystalline properties obtained from macroscopic nuclear models. As a result, we find that the frequencies of fundamental torsional oscillations are sensitive to the density dependence of the symmetry energy, but almost independent of the incompressibility of symmetric nuclear matter. Identifying the lowest frequency among the quasi-periodic oscillations observed in the giant flares as the fundamental ℓ = 2 torsional oscillations, we put constraints on the density derivative of the symmetry energy as L ≃ 50 MeV.