<i>g</i> -mode oscillations of dark matter admixed neutron stars

ABSTRACT We investigate g-mode oscillations in dark matter admixed neutron stars employing a relativistic mean field model to describe hadronic matter and a model for self-interacting fermionic dark matter motivated by the neutron decay anomaly. Following the construction of such admixed configurations, we derive the equilibrium and adiabatic speeds of sound therein, leading to a computation of the star’s g-mode spectrum in the Cowling approximation. In particular, we explore the effect of dark matter self-interaction, the nucleon effective mass, and dark matter fraction on the principal g-mode frequency, and its first overtone. We show that the effect on g-mode frequency depends predominantly on the dark matter fraction, and demonstrate an equation of state-independent constraint for the latter. Prospects of identifying the presence of dark matter in neutron stars using g modes are discussed.