Princeton University Gravity Initiative Seminar

Abstract: The extreme-density environments inside neutron stars provide a unique natural testbed for probing nuclear physics. In the first part of this talk, I will explain how gamma-ray burst observations can be used to extract information about post-merger remnants of binary neutron star mergers, and how multimessenger observations of neutron stars can constrain the nuclear matter equation of state. In the second part, I will focus on probing pressure anisotropy inside neutron stars, motivated by various physical mechanisms including elasticity and magnetic fields. Adopting a phenomenological anisotropy model, we find that, unlike the isotropic-pressure case, anisotropic neutron stars can be unstable to non-radial pulsations. Using a quasi-universal relation between the tidal deformability and the fundamental oscillation frequency, we derive equation-of-state–independent constraints on the degree of pressure anisotropy from gravitational-wave observations.