Gravitational waveforms from spectral Einstein code simulations: Neutron star-neutron star and low-mass black hole-neutron star binaries
Gravitational waveforms from spectral Einstein code simulations: Neutron star-neutron star and low-mass black hole-neutron star binaries
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DOI：
10.1103/physrevd.99.044008
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发表时间：
2018-12
影响因子：
5
通讯作者：
F. Foucart;Matthew D. Duez;T. Hinderer;Jesus Caro;A. Williamson;M. Boyle;A. Buonanno;R. Haas;D. Hemberger;Lawrence E. Kidder;H. Pfeiffer;M. Scheel
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作者：
F. Foucart;Matthew D. Duez;T. Hinderer;Jesus Caro;A. Williamson;M. Boyle;A. Buonanno;R. Haas;D. Hemberger;Lawrence E. Kidder;H. Pfeiffer;M. Scheel
数值模拟得到的引力波形是测试和分析校准用于研究合并致密物体性质的波形模型的关键工具。在本文中，我们提出了一系列的高精度波形产生的频谱爱因斯坦代码（SpEC）的系统涉及至少一个中子星星。我们提供了第一次波形与亚弧度精度超过20个周期的低质量黑洞中子星星二进制文件，包括二进制文件与nonspinning对象，和二进制文件与快速旋转的中子星，最大限度地提高对引力波信号的近共振增长的中子星星的基本激发模式（f-模式）的影响。我们还提供了第一次与SpEC高精度中子星-中子星星波形。这些波形作为SxS目录的一部分公开提供。我们将我们的结果与目前在数据分析管道中实现的分析波形模型进行比较。对于大多数模拟，模型位于合并前最后几个轨道的预测数值误差之外，但没有显示出与数值结果的系统偏差：比较不同的模型似乎提供了合理的建模误差估计。唯一的例外是使用快速反向旋转的中子星星的等质量模拟，以最大限度地提高f-模式的激发的影响，所有的模型表现不佳。然而，这是预期的，因为即使是考虑f-模式激发的单一模型也忽略了中子星星自旋对f-模式激发频率的显著影响。
Gravitational waveforms from numerical simulations are a critical tool to test and analytically calibrate the waveform models used to study the properties of merging compact objects. In this paper, we present a series of high-accuracy waveforms produced with the spectral Einstein code (SpEC) for systems involving at least one neutron star. We provide for the first time waveforms with subradian accuracy over more than twenty cycles for low-mass black hole-neutron star binaries, including binaries with nonspinning objects, and binaries with rapidly spinning neutron stars that maximize the impact on the gravitational wave signal of the near-resonant growth of the fundamental excitation mode of the neutron star (f-mode). We also provide for the first time with SpEC a high-accuracy neutron star-neutron star waveform. These waveforms are made publicly available as part of the SxS catalogue. We compare our results to analytical waveform models currently implemented in data analysis pipelines. For most simulations, the models lie outside of the predicted numerical errors in the last few orbits before merger, but do not show systematic deviations from the numerical results: comparing different models appears to provide reasonable estimates of the modeling errors. The sole exception is the equal-mass simulation using a rapidly counterrotating neutron star to maximize the impact of the excitation of the f-mode, for which all models perform poorly. This is however expected, as even the single model that takes f-mode excitation into account ignores the significant impact of the neutron star spin on the f-mode excitation frequency.