标题： 为行动回放做好准备：利用引力波早期预警的透镜效应 显示英文标题

标题： Gear-up for the Action Replay: Leveraging Lensing for Enhanced Gravitational-Wave Early-Warning

摘要： 在合并前的引力波（GW）天空定位中，双中子星（BNS）和中子星黑洞（NSBH）合并事件将使望远镜能够捕捉合并时刻的前兆和电磁（EM）辐射。我们提出了一种新的天体物理情景，如果这些事件被引力透镜所影响，那么在合并前几小时到几天内，可以提供早期预警，并实现亚角秒级的定位。关键思想是，如果BNS/NSBH被透镜化，那么通过电磁对应体识别的宿主星系也必须被透镜化。根据透镜化宿主星系图像的角分离度、其红移以及（前景）透镜红移，我们证明了在假设标准透镜模型的情况下，可以预测时间延迟。受到我们估计的即将到来的LIGO-Virgo-Kagra观测运行以及第三代网络中透镜化BNS/NSBH合并的检测率的非平凡上限的鼓舞，我们评估了我们方法的可行性和优势。为此，我们研究了望远镜有限的角分辨率对我们预测时间延迟能力的影响。我们发现，当角分辨率为$0.05''$时，在最佳情况下，我们可以预测时间延迟为$> 1$天，误差范围为$\mathcal{O}$（小时）的$1\sigma$。我们还构建了可探测的透镜化BNSs/NSBHs的真实时间延迟分布，以预测我们在所考虑的观测场景中可能预期的早期预警时间。 显示英文摘要

摘要： Pre-merger gravitational-wave (GW) sky-localisation of binary neutron star (BNS) and neutron star black hole (NSBH) coalescence events, would enable telescopes to capture precursors and electromagnetic (EM) emissions around the time of the merger. We propose a novel astrophysical scenario that could provide early-warning times of hours to days before coalescence with sub-arcsecond localisation, provided that these events are gravitationally lensed. The key idea is that if the BNS/NSBH is lensed, then so must the host galaxy identified via the EM counterpart. From the angular separation of the lensed host galaxy images, as well as its redshift and the (foreground) lens redshift, we demonstrate that we can predict the time delays assuming a standard lens model. Encouraged by the non-trivial upper limits on the detection rates of lensed BNS/NSBH mergers that we estimate for upcoming observing runs of the LIGO-Virgo-Kagra and third generation networks, we assess the feasibility and benefits of our method. To that end, we study the effect of limited angular resolution of the telescopes on our ability to predict the time delays. We find that with an angular resolution of $0.05''$, we can predict time delays of $> 1$ day with $1\sigma$ error-bar of $\mathcal{O}$(hours) at best. We also construct realistic time delay distributions of detectable lensed BNSs/NSBHs to forecast the early-warning times we might expect in the observing scenarios we consider.