Institut für Theoretische Physik, Max-von-Laue-Straße 1, 60438 Frankfurt, Germany.
Institut für Theoretische Physik, Max-von-Laue-Straße 1, 60438 Frankfurt, Germany and Max-Planck-Institut für Gravitationsphysik, Albert Einstein Institut, Am Mühlenberg 1, 14476 Potsdam, Germany.
Phys Rev Lett. 2014 Aug 29;113(9):091104. doi: 10.1103/PhysRevLett.113.091104. Epub 2014 Aug 28.
Determining the equation of state of matter at nuclear density and hence the structure of neutron stars has been a riddle for decades. We show how the imminent detection of gravitational waves from merging neutron star binaries can be used to solve this riddle. Using a large number of accurate numerical-relativity simulations of binaries with nuclear equations of state, we find that the postmerger emission is characterized by two distinct and robust spectral features. While the high-frequency peak has already been associated with the oscillations of the hypermassive neutron star produced by the merger and depends on the equation of state, a new correlation emerges between the low-frequency peak, related to the merger process, and the total compactness of the stars in the binary. More importantly, such a correlation is essentially universal, thus providing a powerful tool to set tight constraints on the equation of state. If the mass of the binary is known from the inspiral signal, the combined use of the two frequency peaks sets four simultaneous constraints to be satisfied. Ideally, even a single detection would be sufficient to select one equation of state over the others. We test our approach with simulated data and verify it works well for all the equations of state considered.
确定核密度下物质的物态方程，从而确定中子星的结构，几十年来一直是个谜。我们展示了即将探测到的合并中子星双星的引力波如何用于解决这个难题。我们利用大量具有核物态方程的双星的精确数值相对论模拟，发现合并后的发射特征是两个不同且稳健的谱特征。虽然高频峰值已经与合并产生的超重中子星的振荡有关，并取决于物态方程，但在与合并过程相关的低频峰值和双星中恒星的总紧凑度之间出现了新的相关性。更重要的是，这种相关性本质上是普遍的，因此为物态方程提供了一个强有力的约束工具。如果双星的质量可以从进动信号中得知，那么两个频率峰值的组合将设置四个同时满足的约束条件。理想情况下，即使单次探测也足以从其他物态方程中选择一种。我们用模拟数据测试了我们的方法，并验证了它对所有考虑的物态方程都适用良好。
