Sub-radian-accuracy gravitational waves from coalescing binary neutron stars in numerical relativity. II. Systematic study on the equation of state, binary mass, and mass ratio
Sub-radian-accuracy gravitational waves from coalescing binary neutron stars in numerical relativity. II. Systematic study on the equation of state, binary mass, and mass ratio
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DOI：
10.1103/physrevd.101.084006
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发表时间：
2019-07
影响因子：
5
通讯作者：
K. Kiuchi;K. Kawaguchi;K. Kyutoku;Y. Sekiguchi;M. Shibata
中科院分区：
文献类型：
--
作者：
K. Kiuchi;K. Kawaguchi;K. Kyutoku;Y. Sekiguchi;M. Shibata
我们使用自适应网格细化数值相对论代码{\tt SACRA-MPI}报告了具有6个网格分辨率的26个非旋转二元中子星星系统的数值相对论模拟结果。最好的网格间距是$\约64$-85 $米，这取决于系统。首先，我们推导出长期的高精度inspiral引力波形，并表明，由于有限的网格分辨率的累积引力波相位误差小于0.5 $拉德在超过200 $拉德的相位演化的系统无关。我们还发现，一个二元系统的引力波相位误差与一个表列状态方程（EOS）是可比的分段多方状态方程。然后对SACRA螺旋形重力波形模板进行了验证，发现在重力波频率为1000 $ Hz的范围内，波形模型的精度在重力波相位为$\lesssim 0.1$ rad，在重力波振幅为$\lesssim 20 \%$。最后，我们校准了文献中提出的合并后引力波信号与潮汐形变率/中子星星半径之间的普适关系，并表明它们受到系统论的影响，许多被提出作为普适关系的关系并不是很普适。提出了改进的拟合公式。
We report results of numerical relativity simulations for {\it new} 26 non-spinning binary neutron star systems with 6 grid resolutions using an adaptive mesh refinement numerical re\ lativity code {\tt SACRA-MPI}. The finest grid spacing is $\approx 64$--$85$ m, depending on the systems. First, we derive long-term high-precision inspiral gravitational waveforms and show that the accumulated gravitational-wave phase error due to the finite grid resolution is less than $0.5$ rad during more than $200$ rad phase evolution irrespective of the systems. We also find that the gravitational-wave phase error for a binary system with a tabulated equation of state (EOS) is comparable to that for a piecewise polytropic EOS. Then we validate the SACRA inspiral gravitational waveform template, which will be used to extract tidal deformability from gravitational wave observation, and find that accuracy of \ our waveform modeling is $\lesssim 0.1$ rad in the gravitational-wave phase and $\lesssim 20 \%$ in the gravitational-wave amplitude up to the gravitational-wave frequency $1000$ Hz.\ Finally, we calibrate the proposed universal relations between a post-merger gravitational wave signal and tidal deformability/neutron star radius in the literature and show that th\ ey suffer from systematics and many relations proposed as universal are not very universal. Improved fitting formulae are also proposed.