论文标题
二进制中子星星后连续性动力学中微物理散装粘度的出现
Emergence of microphysical bulk viscosity in binary neutron star post-merger dynamics
论文作者
论文摘要
在孤立的中子星中的核物质中，风味含量（例如质子馏分）会受到弱相互作用，从而建立了风味（$β$ - ）平衡。但是，在两个中子星的合并期间，这种平衡可能存在偏差。我们通过将直接和修改的URCA过程（在中微子 - 透明度制度）结合到一般性流体动力学模拟中，并使用简化的中微子运输方案来研究碰撞过程中所得的平衡动力学。我们展示了合并后模拟中如何脱离和评估所得流量的散装粘性动力学中的弱相互作用驱动的体积粘度。我们进一步对合并后重力波应变的影响提出了限制。我们的结果表明，弱交互驱动的体积粘度可能会导致合并后重力波谱的相移，尽管该效果目前与我们模拟的数值误差相同。
In nuclear matter in isolated neutron stars, the flavor content (e.g., proton fraction) is subject to weak interactions, establishing flavor ($β$-)equilibrium. However, there can be deviations from this equilibrium during the merger of two neutron stars. We study the resulting out-of-equilibrium dynamics during the collision by incorporating direct and modified Urca processes (in the neutrino-transparent regime) into general-relativistic hydrodynamics simulations with a simplified neutrino transport scheme. We demonstrate how weak-interaction-driven bulk viscosity in post-merger simulations can emerge and assess the bulk viscous dynamics of the resulting flow. We further place limits on the impact on the post-merger gravitational wave strain. Our results show that weak-interaction-driven bulk viscosity can potentially lead to a phase shift of the post-merger gravitational wave spectrum, although the effect is currently on the same level as the numerical errors of our simulation.
