论文标题
镜头重力波的明显超浮力
Apparent Superluminality of Lensed Gravitational Waves
论文作者
论文摘要
我们考虑具有相关电磁(EM)对应物的引力波(GW)源,并在存在镜头的情况下分析两个信号之间的时间延迟。如果GW的波长与天体物理透镜的Schwarzschild半径相当,则必须使用波光学元件处理它们,而EM波通常符合几何光学元件的近似值。使用具体的示例,我们确认GW信号在EM对应物之前永远不会到达,如果两者都同时发射。但是,在二进制的灵感中,GW波形的峰值可以在其EM对应物之前到达。我们强调,这只是明显的超亮性,因为GW波形既扭曲又相对于光线而进一步延迟。在任何情况下,测量多通信的时间延迟并正确解释其对揭示镜片的分布,测试重力的性质以及探测宇宙学扩展历史具有重要意义。
We consider gravitational wave (GW) sources with an associated electromagnetic (EM) counterpart, and analyze the time delay between both signals in the presence of lensing. If GWs have wavelengths comparable to the Schwarzschild radius of astrophysical lenses, they must be treated with wave optics, whereas EM waves are typically well within the approximation of geometric optics. With concrete examples, we confirm that the GW signal never arrives before its EM counterpart, if both are emitted at the same time. However, during the inspiral of a binary, peaks of the GW waveform can arrive before their EM counterpart. We stress this is only an apparent superluminality since the GW waveform is both distorted and further delayed with respect to light. In any case, measuring the multi-messenger time delay and correctly interpreting it has important implications for unveiling the distribution of lenses, testing the nature of gravity, and probing the cosmological expansion history.