The nuclear symmetry energy plays a key role in determining the equation of state of dense, neutron-rich matter, which governs the properties of both terrestrial nuclear matter as well as astrophysical neutron stars. A recent measurement of the neutron skin thickness from the PREX Collaboration has lead to new constraints on the slope of the nuclear symmetry energy, $L$, which can be directly compared to inferences from gravitational wave observations of the first binary neutron star merger inspiral, GW170817. In this paper, we explore a new regime for potentially constraining the slope, $L$, of the nuclear symmetry energy with future gravitational wave events: the post-merger phase of a binary neutron star coalescence. In particular, we go beyond the inspiral phase, where imprints of the slope parameter $L$ may be inferred from measurements of the tidal deformability, to consider imprints on the post-merger dynamics, gravitational wave emission, and dynamical mass ejection. To this end, we perform a set of targeted neutron star merger simulations in full general relativity using new finite-temperature equations of state, which systematically vary $L$ while keeping the magnitude of the symmetry energy at the saturation density, $S$, fixed. We find that the post-merger dynamics and gravitational wave emission are mostly insensitive to the slope of the nuclear symmetry energy. In contrast, we find that dynamical mass ejection contains a weak imprint of $L$, with large values of $L$ leading to systematically enhanced ejecta.

中文翻译：

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核对称能对双中子星合并后合并阶段的影响

核对称能在确定稠密、富含中子物质的状态方程方面起着关键作用，它控制着地球核物质和天体物理中子星的性质。最近来自 PREX Collaboration 的中子蒙皮厚度测量结果对核对称能量的斜率产生了新的限制，$升$，这可以直接与第一个双中子星合并螺旋线 GW170817 的引力波观测结果进行比较。在本文中，我们探索了一种可能限制斜率的新机制，$升$, 未来引力波事件的核对称能量：双中子星合并的后合并阶段。特别是，我们超越了吸气阶段，在那里斜率参数的印记$升$可以从潮汐变形性的测量中推断出来，以考虑对合并后动力学、引力波发射和动力学物质抛射的影响。为此，我们使用新的有限温度状态方程在完全广义相对论中进行了一组目标中子星合并模拟，这些方程系统地变化$升$ 在将对称能的大小保持在饱和密度的同时， $秒$， 固定的。我们发现合并后的动力学和引力波发射大多对核对称能量的斜率不敏感。相比之下，我们发现动态物质抛射包含一个微弱的印记$升$, 具有很大的值 $升$ 导致系统性增强的喷射物。