Measuring the Gravitomagnetic Distortion from Rotating Halos. I. Methods
Measuring the Gravitomagnetic Distortion from Rotating Halos. I. Methods
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DOI：
10.3847/1538-4357/abe69e
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发表时间：
2020-09
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影响因子：
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通讯作者：
Chengfeng Tang;Pierre Zhang;Wentao Luo;Nan Li;Yi-Fu Cai;Shi Pi
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作者：
Chengfeng Tang;Pierre Zhang;Wentao Luo;Nan Li;Yi-Fu Cai;Shi Pi
源星系的图像不仅受到静态引力势的影响，还受到星系团等大质量旋转物体引起的坐标系拖曳的影响。这种效应在理论上已得到很好的理解;因此，估计其可探测性以供今后的调查十分重要。在这项工作中，我们分析了旋转暗物质晕周围的透镜收敛κ。大质量物体的旋转产生了引力磁势，从而对透镜势产生了各向异性贡献。我们构造了一个估计量δ κ来描述κ在晕旋转轴周围的对称增强和减小之间的差异，发现它可以很好地近似为与晕速度色散平方乘以无量纲角动量参数成比例的函数。使用具有现实噪声水平的模拟模拟，例如空间和时间的传统调查（LSST），我们测试了我们的估计器，并表明堆叠旋转透镜的帧拖动信号在1σ内与零一致。然而，我们发现SDSS DR 7光谱选群表中质量最大的星团的视向自转速度为195.0 km s−1，速度色散为667.8 km s−1，根据N体模拟的角动量概率分布，这是1.2 × 10−8的几率。通过研究SDSS DR 7光谱选定的组目录，我们展示了如何旋转的集群可以识别，并发现快速旋转的集群可能比基于模拟的估计更丰富，在未来的调查中可能会检测到重力磁畸变。
Source galaxy images are distorted not only by a static gravitational potential, but also by frame-dragging induced by massive rotating objects like clusters of galaxies. Such an effect is well understood theoretically; it is therefore of great interest to estimate its detectability for future surveys. In this work, we analyze the lensing convergence κ around rotating dark matter halos. The rotation of the massive objects generates a gravitomagnetic potential giving rise to an anisotropic contribution to the lensing potential. We construct an estimator δ κ to describe the difference between the symmetric enhancement and reduction of κ around the halo rotation axis, finding that it is well approximated by a function proportional to the halo velocity dispersion squared times a dimensionless angular momentum parameter. Using simulation mocks with realistic noise level for a survey like the Legacy Survey of Space and Time (LSST), we test our estimator, and show that the signal from frame-dragging of stacked rotating lenses is consistent with zero within 1σ. However, we find that the most massive cluster in SDSS DR7 spectroscopic selected group catalog has a line-of-sight rotation velocity of 195.0 km s−1 and velocity dispersion of 667.8 km s−1, which is at 1.2 × 10−8 odds according to the angular momentum probability distribution inferred from N-body simulations. By studying SDSS DR7 spectroscopic selected group catalog, we show how rotating clusters can be identified, and, finding that fast rotating clusters might be more abundant than in estimates based on simulations, a detection of gravitomagnetic distortion may be at reach in future surveys.