论文标题
部分可观测时空混沌系统的无模型预测
Testing Velocity-Field Lensing on IllustrisTNG Galaxies
论文作者
论文摘要
如果有有关源星系的发明属性的信息，则可以更精确地测量引力透镜剪切。磁盘星系速度字段至少在原则上提供了此类信息，当使用速度场观测值来补充图像时，理想化的模型可预测数量级的数量级。为了测试磁盘星系的现实特征（WARPS，条，螺旋臂和其他子结构）在此类剪切测量中注入噪声或偏置的水平，我们在Illustris TNG100模拟中拟合了理想化的磁盘模型，包括剪切模型，包括剪切的星系。因此，推断的剪切表明未建模的星系特征注入噪声和偏置的程度。我们发现$γ_+$是与银河系的第一个主轴平行的剪切组成部分，是高度偏见且嘈杂的，因为磁盘违反了面对面的圆形假设，显示了一系列固有的轴比率（$ 0.85 \ pm0.11 $）。另一个剪切组件，$γ_\ times $，显示出很小的偏见，并通过双核分布的双层分布很好地描述了中央核心散点$σ_ {\ text {core}} \ $ 0.03，大约$ 0.03，低振幅，宽阔的机翼。这是提出的速度场透镜技术中自然噪声底的第一个测量。我们得出的结论是，该技术将获得$γ_\ times $的衡量标准的令人印象深刻的精确性，但是对于$γ_+$的测量值很少。
Weak gravitational lensing shear could be measured far more precisely if information about unlensed attributes of source galaxies were available. Disk galaxy velocity fields supply such information, at least in principle, with idealized models predicting orders of magnitude more Fisher information when velocity field observations are used to complement images. To test the level at which realistic features of disk galaxies (warps, bars, spiral arms, and other substructure) inject noise or bias into such shear measurements, we fit an idealized disk model, including shear, to unsheared galaxies in the Illustris TNG100 simulation. The inferred shear thus indicates the extent to which unmodeled galaxy features inject noise and bias. We find that $γ_+$, the component of shear parallel to the galaxy's first principal axis, is highly biased and noisy because disks violate the assumption of face-on circularity, displaying a range of intrinsic axis ratios ($0.85\pm0.11$). The other shear component, $γ_\times$, shows little bias and is well-described by a double Gaussian distribution with central core scatter $σ_{\text{core}} \approx$ 0.03, with low-amplitude, broad wings. This is the first measurement of the natural noise floor in the proposed velocity-field lensing technique. We conclude that the technique will achieve impressive precision gains for measurements of $γ_\times$, but little gain for measurements of $γ_+$.
