We construct quasinormal modes for neutron stars in R2 gravity in the Einstein frame, considering scalar masses in the sub-neV range. In particular, we investigate the fundamental quadrupole fluid f-modes and the dipole fluid F-modes. Employing six equations of state covering matter content with nucleons, hyperons, and quarks, we then propose universal relations for the quadrupole f-modes and dipole F-modes. The dipole F-modes are ultra-long lived and, for the lower scalar masses, their frequencies are inversely proportional to the corresponding Compton wavelength.
@article{arxiv.2205.03283,
title = {Universal relations for quasinormal modes of neutron stars in $R^2$ gravity},
author = {J. L. Blázquez-Salcedo and L. M. González-Romero and F. S. Khoo and J. Kunz and V. Preut},
journal= {arXiv preprint arXiv:2205.03283},
year = {2022}
}