Initial-data contribution to the error budget of gravitational waves from neutron-star binaries
Initial-data contribution to the error budget of gravitational waves from neutron-star binaries
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初始数据对中子星双星引力波误差预算的贡献
DOI：
10.1103/physrevd.94.044049
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发表时间：
2016
影响因子：
5
通讯作者：
Uryū, Kōji
中科院分区：
文献类型：
--
作者：
Tsokaros, Antonios;Mundim, Bruno C.;Galeazzi, Filippo;Rezzolla, Luciano;Uryū, Kōji
由于数值计算的吸气中子星双星达到的准确度值与黑洞双星，一个良好的预算的各种来源的错误变得越来越重要。在这些来源中，初始数据通常不被考虑，其理由是初始类空超曲面上的误差总是远远小于演化过程中获得的误差。在这里，我们认真考虑这个假设，并进行比较分析的重力波形相对于基本上相同的物理二进制配置时，计算两个不同的初始数据代码，然后用相同的演化代码演变。更具体地说，我们认为无论是与伪谱codelorene计算的无旋中子星双星的演变，或与新开发的有限差分coderal;这两组初始数据随后演变的高阶演化codewiskythc。这样，我们发现，尽管系统的整体量，如质量和角动量，有数量级的差异，但局部量，如静止质量密度，非本征曲率或角速度，表现出更大的逐点差异，数量级。这些局部的差异，然后负责在合并时间（大约三个轨道后）的引力波的弗拉第亚星系的相移。我们的研究结果强调了使用初始数据的重要性，这些数据在进行比较研究和估计物理参数时是完全相同的。
As numerical calculations of inspiraling neutron-star binaries reach values of accuracy that are comparable with those of black-hole binaries, a fine budgeting of the various sources of error becomes increasingly important. Among such sources, the initial data are normally not accounted for, the rationale being that the error on the initial spacelike hypersurface is always far smaller than the error gained during the evolution. We here consider critically this assumption and perform a comparative analysis of the gravitational waveforms relative to essentially the same physical binary configuration when computed with two different initial-data codes, and then evolved with the same evolution code. More specifically, we consider the evolution of irrotational neutron-star binaries computed either with the pseudospectral codelorene, or with the newly developed finite-difference codecocal; both sets of initial data are subsequently evolved with the high-order-evolution codewhiskythc. In this way we find that althoughglobalquantities of the system, like the mass and angular momentum, have differences of the order of,localquantities, like rest-mass density, extrinsic curvature or angular velocity, show pointwise differences that are much larger, of the order of. These local differences are then responsible for a dephasing in the gravitational waves at the merger time (after approximately three orbits) ofradians. Our results highlight the importance of using initial data that are pointwisely the same when comparative studies are done and physical parameters are estimated.