Binary neutron stars with generic spin, eccentricity, mass ratio, and compactness: Quasi-equilibrium sequences and first evolutions
Binary neutron stars with generic spin, eccentricity, mass ratio, and compactness: Quasi-equilibrium sequences and first evolutions
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具有通用自旋、偏心率、质量比和致密性的双中子星：准平衡序列和首次演化
DOI：
10.1103/physrevd.92.124007
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发表时间：
2015
影响因子：
5
通讯作者：
W. Tichy
中科院分区：
文献类型：
--
作者：
T. Dietrich;N. Moldenhauer;N. K. Johnson-McDaniel;S. Bernuzzi;C. M. Markakis;B. Brügmann;W. Tichy
从准平衡构型和动力学演化中可以提取关于双中子星末级、激旋和最终合并的信息。在这篇文章中，我们构造了不同自旋、偏心率、质量比、致密性和状态方程的准平衡组态。为此，我们使用了网格代码，它允许我们在以前无法访问的参数空间区域中构建这样的数据。特别是，我们考虑了孤立和双星系统中的中子星自转；我们采用了新的方法来产生高度偏心和偏心减少的数据；我们提供了计算具有质量比的显著不等质量双星的数据的可能性；我们创建了个体紧凑度高达的等质量双星。作为原理的证明，我们研究了三种新构型的动力学演化。首先，我们模拟了迄今为止在数值相对论中演化的双中子星的最高质量比--聚集率。我们发现，在合并之前，伴星的质量传递只需几圈，其余的质量在两颗恒星之间传递。这个质量吸积量对应于吸积能的大小。这种构型还会在Merge()过程中喷出大量物质，对剩余的中子星产生很大的冲击力。其次，我们模拟了进动双星中子星的第一次合并。我们给出了用于进动模拟的引力波的主要模，其中进动的明显印记在(2，1)模中可见。最后，我们量化了偏心减少过程对引力波形的影响。该程序改善了波形质量，并应在未来的精度研究中使用。然而，还需要减少波形中的其他误差，特别是截断误差，以使由于偏心减少而产生的改善有效。
Information about the last stages of a binary neutron star inspiral and the final merger can be extracted from quasiequilibrium configurations and dynamical evolutions. In this article, we construct quasiequilibrium configurations for different spins, eccentricities, mass ratios, compactnesses, and equations of state. For this purpose we employ thesgridcode, which allows us to construct such data in previously inaccessible regions of the parameter space. In particular, we consider spinning neutron stars in isolation and in binary systems; we incorporate new methods to produce highly eccentric and eccentricity-reduced data; we present the possibility of computing data for significantly unequal-mass binaries with mass ratios; and we create equal-mass binaries with individual compactness up to. As a proof of principle, we explore the dynamical evolution of three new configurations. First, we simulate amass ratio which is the highest mass ratio for a binary neutron star evolved in numerical relativity to date. We find that mass transfer from the companion star sets in a few revolutions before merger and a rest mass ofis transferred between the two stars. This amount of mass accretion corresponds toof accretion energy. This configuration also ejects a large amount of material during merger (), imparting a substantial kick to the remnant neutron star. Second, we simulate the first merger of a precessing binary neutron star. We present the dominant modes of the gravitational waves for the precessing simulation, where a clear imprint of the precession is visible in the (2,1) mode. Finally, we quantify the effect of an eccentricity-reduction procedure on the gravitational waveform. The procedure improves the waveform quality and should be employed in future precision studies. However, one also needs to reduce other errors in the waveforms, notably truncation errors, in order for the improvement due to eccentricity reduction to be effective.