Gravitational lensing and microlensing of gravitational-waves

随着地面探测器网络变得更加灵敏，双星黑洞或中子星合并的引力透镜将变得越来越有可能--这将提供一个重要的进一步的强引力探测器，以及一种限制透镜性质的新方法。已经有相当成熟的先前文献探索透镜引力波源的理论特征，LIGO Virgo KAGRA(LVK)的合作已经在建立分析管道来搜索透镜信号方面投入了大量的努力，几篇简短的作者或合作论文展示了这些搜索的结果。然而，许多代码基础设施都集中在点质量透镜上，特别是对于微透镜事件。虽然这在一定程度上是一个合理的假设，但有机会比较不同扩展透镜质量分布的结果是一个重要和及时的机会。该项目的目的是开发新的分析方法，考虑不同的透镜模型，有效地计算它们的透镜放大函数，并允许对它们对候选信号的相对适用性进行贝叶斯模型比较。执行这些计算的代码将被合并到LVK透镜管道中，经过彻底测试，并应用于未来LVK观测运行的数据。还将探讨透镜编码对例如来自第三代地面探测器的数据的更广泛适用性。这项工作的最终目标将是实现对透镜引力波事件的更强探测和对透镜性质的更全面的研究。

As the network of ground-based detectors becomes more sensitive, the gravitational lensing of binary black hole or neutron star merger will become increasingly likely - and will offer both an important further probe of strong gravity and a novel means of constraining the properties of the lens. There is a reasonably mature prior literature exploring the theoretical signatures of lensed gravitational-wave sources, and the LIGO Virgo KAGRA (LVK) Collaborations have already invested significant effort in setting up analysis pipelines to search for lensed signals, with several short-author or collaboration papers presenting the results of those searches. Much of the code infrastructure has focussed on point-mass lenses, however, particularly for microlensing events. While that is partially justified as a reasonable assumption, the opportunity to compare results for different extended lens mass distributions is an important and timely one. The aim of this project is to develop new analysis approaches that consider different lens models, efficiently compute their lensing amplification functions and permit a Bayesian model comparison of their relative applicability to candidate signals. The codes to carry out these calculations will be incorporated into the LVK lensing pipelines, thoroughly tested and applied to data from future LVK observing runs. Wider applicability of the lensing codes to e.g. data from 3rd generation ground-based detectors will also be explored. The ultimate goal of this work will be to allow a more robust detection of a lensed gravitational-wave event and a more complete investigation of the lens properties.