AMR simulations of the low T/|W| bar-mode instability of neutron stars

Abstract

It has been recently argued through numerical work that rotating stars with a high degree of differential rotation are dynamically unstable against bar-mode deformation, even for values of the ratio of rotational kinetic energy to gravitational potential energy as low as O(0.01). This may have implications for gravitational wave astronomy in high-frequency sources such as core collapse supernovae. In this paper we present high-resolution simulations, performed with an adaptive mesh refinement hydrodynamics code, of such low T/|W| bar-mode instability. The complex morphological features involved in the nonlinear dynamics of the instability are revealed in our simulations, which show that the excitation of Kelvin-Helmholtz-like fluid modes outside the corotation radius of the star leads to the saturation of the bar-mode deformation. While the overall trends reported in an earlier investigation are confirmed by our work, we also find that numerical resolution plays an important role during the long-term, nonlinear behaviour of the instability, which has implications on the dynamics of rotating stars and on the attainable amplitudes of the associated gravitational wave signals.

20 pages, 9 figures, accepted for publication in Computer Physics Communications.

References in corpus (1)

• Dynamical bar instability in a relativistic rotational core collapse

Cited by in corpus (9)

• The gravitational wave burst signal from core collapse of rotating stars
• Magnetic effects on the low-T/|W| instability in differentially rotating neutron stars
• The intimate relation between the low T/W instability and the co-rotation point
• Effect of stellar rotation on the development of post-shock instabilities during core-collapse supernovae
• Multimessenger Emission from the Accretion Induced Collapse of White Dwarfs
• Low-$T/|W|$ instabilities in differentially rotating proto-neutron stars with magnetic fields
• Faraday resonance in dynamical bar instability of differentially rotating stars
• Amplification of azimuthal modes with odd wave numbers during dynamical bar-mode growth in rotating stars
• Impact of ultralight bosonic dark matter on the dynamical bar-mode instability of rotating neutron stars