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This study addresses a numerical problem in neutron star simulations where artificial heating occurs at the stellar surface during binary inspiral calculations. The researchers demonstrate that an entropy-based flux-limiting (EFL) scheme successfully reduces this spurious heating effect across multiple neutron star models and binary configurations using hybrid equations of state. The method shows consistent improvement in controlling numerical artifacts associated with steep gradients near the stellar surface.
Why it matters
Accurate neutron star merger simulations are essential for interpreting gravitational wave observations and predicting electromagnetic counterparts from these events. Reducing numerical artifacts improves the reliability of predictions about neutron star properties and merger dynamics, which helps astronomers better understand these extreme cosmic phenomena.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: The treatment of the stellar surface in binary neutron star simulations is crucial for the accuracy of the numerical evolution and the physical reliability of the predicted observables. Numerical artifacts associated with the treatment of steep gradients near the stellar surface can produce spurious heating during the inspiral, leading to an artificial increase of the internal energy and an unphysical expansion of the neutron star. In this work, we investigate the effectiveness of the entropy-based flux-limiting (EFL) scheme in mitigating these numerical effects within the finite-difference code BAM. We perform simulations of both isolated neutron stars and binary neutron star inspirals employing a representative set of hybrid equations of state. We show that the EFL scheme significantly reduces artificial surface heating. This reduction is observed consistently across all stellar models and binary configurations considered, demonstrating that the reduction of numerical heating is a robust feature of the EFL method.