Speaker
Description
Employing relativistic energy density functionals PKDD, DD-ME2, and TW99 for nucleon-nucleon interactions, we investigate the impact of $\Delta$ resonances on the frequencies of non-radial $g$-mode oscillations in neutron stars adopting the universal coupling scheme. Our results show that when the proportion of $\Delta$ resonances in the neutron star interior reaches a certain threshold, the $g$-mode oscillation energy becomes concentrated within the region where $\Delta$ resonances appear, leading to a sharp increase in the $g$-mode frequency. In addition, we also examine the $f$-mode and $p$-mode oscillations and find that the impact of $\Delta$ resonances on these modes is less pronounced than on the $g$-mode. We also compare the oscillation frequencies calculated in the Cowling approximation with those from full general relativity, confirming that the Cowling approximation introduces an error of approximately 20\% for the $f$-mode and within 10\% for the $g$-mode. The notable effect of $\Delta$ resonances on neutron star $g$-mode frequencies holds important implications for probing the internal composition of neutron stars.