Crustal torsional oscillations inside the deeper pasta structures

Abstract

AbstractThe quasiperiodic oscillations (QPOs) have been discovered in the afterglow of the giant flares observed in the soft‐gamma repeaters. As QPOs are strongly associated with the neutron star oscillations, one could extract the neutron star properties via identification of QPOs as specific neutron star oscillations. In this study, we take into account the torsional oscillations inside the phase composed of cylindrical holes (tubes) and spherical holes (bubbles), which correspond to the inner layer in the neutron star crust. We remark that such oscillations are independent of the oscillations inside the phase composed of spherical and cylindrical nuclei, which correspond to the outer layer. Then, we find that all the observed QPOs can be explained with torsional oscillations excited in either layer, which is consistent with the severe constraint on the slope parameter, L, of nuclear symmetry energy as L ≃ 58 − 73 MeV obtained in our previous study.