LISA measurement of gravitational wave background anisotropy: Hexadecapole moment via a correlation analysis
LISA measurement of gravitational wave background anisotropy: Hexadecapole moment via a correlation analysis
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LISA 测量引力波背景各向异性：通过相关分析的十六极矩
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
A. Cooray
中科院分区：
文献类型：
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作者：
N. Seto;A. Cooray
我们讨论的引力波背景的空间波动所产生的未解决的银河双星源，如密切的白色矮双星，由于事实上的银河双星源分布是各向异性的。我们介绍了一个相关分析的两个数据流的激光干涉仪空间天线（丽莎）提取球谐系数的十六极矩（l = 4）的投影二维密度分布的二进制源人口在一个独立的方式。在这个分析中，我们使用一个自由参数，我们可以有效地控制丽莎的车轮旋转的频率。所提出的技术补充和改进了以前的建议，在文献中测量的引力波背景各向异性的基础上的时间调制的数据作为丽莎围绕太阳的轨道。然而，这种技术仅限于星系球谐系数的某些组合，无法单独分离它们。在一定的坐标系下，用丽莎可以测量m = 2，3，4的十六极（l = 4）系数，信噪比在10级以上。除了十六极系数外，当与时间调制分析相结合时，相关研究原则上也可以用于测量二元分布的四极系数。
We discuss spatial fluctuations in the gravitational wave background arising from unresolved Galactic binary sources, such as close white dwarf binaries, due to the fact the galactic binary source distribution is anisotropic. We introduce a correlation analysis of the two data streams of the Laser Interferometer Space Antenna (LISA) to extract spherical harmonic coefficients of the hexadecapole moment (l = 4) related to the projected two-dimensional density distribution of the binary source population in an independent manner. In this analysis, we use a free parameter with which we can effectively control the frequency of the cartwheel rotation of LISA. The proposed technique complements and improves over previous suggestions in the literature to measure the gravitational wave background anisotropy based on the time modulation of data as LISA orbits around the Sun. Such techniques, however, are restricted only to certain combinations of spherical harmonic coefficients of the galaxy with no ability to separate them individually. With LISA, m = 2,3 and 4 coefficients of the hexadecapole (l = 4) can be measured with signal-to-noise ratios at the level of ten and above in a certain coordinate system. In addition to the hexadecapole coefficients, when combined with the time modulation analysis, the correlation study also can be used, in principle, to measure quadrupole coefficients of the binary distribution.