Nonconformally flat initial data for binary compact objects
Nonconformally flat initial data for binary compact objects
复制标题
二进制紧凑对象的非共形平坦初始数据
DOI：
10.1103/physrevd.80.124004
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发表时间：
2009
影响因子：
5
通讯作者：
M. Shibata
中科院分区：
文献类型：
--
作者：
K. Uryū;F. Limousin;J. Friedman;E. Gourgoulhon;M. Shibata
本文介绍了一种构造准平衡圆轨道中子星双星系统初始数据的新方法。非共形平坦的数据，无波和近区螺旋对称的两个配方，在每个配方中，爱因斯坦-欧拉系统，写在3 +1$形式上的渐近平坦的类空超曲面，精确求解所有度量组件，包括空间非共形平坦的潜力，和无旋流。一个适用于这两种配方的数值方法解释强调施加的空间规范条件。结果显示的解决方案序列的无旋二进制中子星的物质近似的参数化状态方程，使用几段多变的状态方程。对于更紧凑的恒星，在共形平坦\char 22 {}Isenberg-Wilson-Mathews\char 22 {}公式中计算的解序列的结合能和总角动量更接近于第三后牛顿（3 PN）两点粒子的结合能和总角动量，直到最近的轨道，而由无波/近波产生的序列，对于具有较大紧凑性的序列，区域螺旋对称公式甚至更多地偏离3 PN曲线。我们认为，这可能是因为这个修正反映了在伊森伯格-威尔逊-马修斯公式以及在3 PN公式高估，由$\ensuremath{\sim}1$周期的引力波阶段在最后几个轨道。这项工作表明，实施空间共形平坦度的结果低估了四极变形的组件的二进制中子星系统在最后几个轨道合并之前。
A new method is described for constructing initial data for a binary neutron-star system in quasiequilibrium circular orbit. Two formulations for nonconformally flat data, waveless and near-zone helically symmetric, are introduced; in each formulation, the Einstein-Euler system, written in $3+1$ form on an asymptotically flat spacelike hypersurface, is exactly solved for all metric components, including the spatially nonconformally flat potentials, and for irrotational flow. A numerical method applicable to both formulations is explained with an emphasis on the imposition of a spatial gauge condition. Results are shown for solution sequences of irrotational binary neutron-stars with matter approximated by parametrized equations of state that use a few segments of polytropic equations of state. The binding energy and total angular momentum of solution sequences computed within the conformally flat\char22{}Isenberg-Wilson-Mathews\char22{}formulation are closer to those of the third post-Newtonian (3PN) two point particles up to the closest orbits, for the more compact stars, whereas sequences resulting from the waveless/near-zone helically symmetric formulations deviate from the 3PN curve even more for the sequences with larger compactness. We think it likely that this correction reflects an overestimation in the Isenberg-Wilson-Mathews formulation as well as in the 3PN formula, by $\ensuremath{\sim}1$ cycle in the gravitational-wave phase during the last several orbits. The work suggests that imposing spatial conformal flatness results in an underestimate of the quadrupole deformation of the components of binary neutron-star systems in the last few orbits prior to merger.
相对论中子星合并产生的引力波与微物理状态方程
影响因子：
8.6
作者：
R. Oechslin;H.-Th. Janka
通讯作者：
H.-Th. Janka