[论文解读] On the detection and precise localisation of merging black holes events through strong gravitational lensing

Ewoud Wempe, L. V. E. Koopmans+3 more|arXiv (Cornell University)|Apr 19, 2022

Pulsars and Gravitational Waves Research参考文献 97被引用 7

一句话总结

本文提出利用强引力透镜效应，通过将LIGO-Virgo-KAGRA探测到的引力波信号与类似Euclid的巡天计划的电磁数据交叉匹配，精确本地化合并黑洞事件。研究发现，21.9–34.6%的四重像透镜事件可凭借高后验概率正确识别为透镜事件，实现亚毫角秒级定位；尽管首次探测可能需要深度后续观测和探测器灵敏度的提升。

ABSTRACT

To unlock the full spectrum of astrophysical and cosmological applications of gravitational-wave detections, it is essential to localise the associated black-hole mergers to high precision inside their host galaxies. One possible method to achieve this is to compare the properties of multiple detections of gravitationally-lensed binary black-hole merger events with the properties of strong gravitational lens systems located in the joint sky localisation of the gravitational-wave detections. In this work, we simulate the population of binary black-hole mergers lensed by galaxy-scale lenses and detectable by LIGO-Virgo-Kagra in the coming decade and the population of galaxy-scale strong lenses that will be detected by Euclid. We use these simulations to investigate the prospects for localising strongly lensed binary black-hole mergers inside the lensed galaxies of 'Euclid-like' galaxy-scale strong lenses. We find that for 20-50% of strongly lensed gravitational wave events the lens system is detectable with Euclid, if the event falls in its survey footprint. Of these, we expect to correctly identify the strongly-lensed host galaxy as likely (with posterior probability) host galaxy - based on Bayesian evidence ranking of candidate hosts - for 34.6-21.9% of quadruply-lensed gravitational-wave events when given an a-priori 1-5 deg^2 gravitational-wave-only sky localisation. For triply and doubly lensed gravitational-wave events, this becomes 29.8-14.9% and 16.4-6.6% respectively. If successfully identified, however, the localisation can be better than a fraction of the host-galaxy size, i.e. of order milli-arcseconds. A first detection in the coming decade, however, probably requires dedicated deep and high-resolution follow-ups and continued upgrades in the current and planned gravitational-wave detectors.

研究动机与目标

• 研究利用LIGO-Virgo-KAGRA的多信使数据（引力波与电磁巡天）精确本地化强透镜双黑洞并合事件的可行性。
• 评估未来类似Euclid的巡天计划探测引力波事件透镜星系的概率。
• 基于贝叶斯证据排序，量化对透镜引力波事件宿主星系识别的准确性。
• 评估天空本地化不确定性对识别透镜宿主星系成功率的影响。
• 探索利用电磁数据独立验证引力波强透镜探测的潜力。

提出的方法

• 模拟未来十年内由星系尺度透镜可探测的、被LIGO-Virgo-KAGRA探测到的双黑洞并合事件群体。
• 生成合成的透镜引力波信号，并将其与模拟的类似Euclid巡天中的强透镜系统匹配。
• 使用贝叶斯证据排序法，在引力波天空本地化区域内比较候选宿主星系。
• 应用重要性采样，估计每个候选透镜-宿主星系系统在给定引力波数据和透镜模型下的边际似然。
• 在似然框架中引入对透镜和源物理性质的先验信息，以提高识别准确性。
• 评估该方法在不同透镜配置（四重像、三重像和双像透镜事件）下的性能表现。

实验结果

研究问题

• RQ1 在LIGO-Virgo-KAGRA探测到的强透镜双黑洞并合事件中，有多少比例的透镜系统可通过Euclid探测到（若事件位于其巡天覆盖范围内）？
• RQ2 在使用贝叶斯证据排序法时，能多准确地从候选宿主星系中识别出透镜引力波事件的真实宿主星系？
• RQ3 利用多信使数据，对透镜引力波事件能达到多高的天空本地化精度？
• RQ4 探测效率如何随透镜多重性（四重像 vs. 三重像 vs. 双重像透镜事件）而变化？
• RQ5 对透镜引力波事件进行电磁后续观测，能否提供独立的强透镜效应确认，从而降低误报率？

主要发现

• 若事件位于其巡天覆盖范围内，预计20%至50%的强透镜引力波事件的透镜系统可被Euclid探测到。
• 对于四重像透镜事件，当引力波天空本地化区域为1–5 deg²时，有21.9%至34.6%可凭借高后验概率正确识别为透镜事件。
• 对于三重像透镜事件，识别成功率在14.9%至29.8%之间；对于双像透镜事件，识别成功率在6.6%至16.4%之间。
• 成功识别后，定位精度可达到亚毫角秒量级，显著优于非透镜事件。
• 未来十年内首次探测到透镜引力波事件，可能需要专门的深度、高分辨率电磁后续观测。
• 该方法可通过电磁数据与透镜假设的交叉验证，实现对强透镜探测的独立确认，从而降低由天体物理巧合引起的误报率。