[论文解读] Coincidence detection of broadband signals by networks of the planned interferometric gravitational wave detectors

B. Bhawal, Sanjeev Dhurandhar|ArXiv.org|Sep 22, 1995

Pulsars and Gravitational Waves Research参考文献 1被引用 6

一句话总结

本文研究了计划中的干涉型引力波探测器网络（LIGO、VIRGO、GEO、AIGO、TAMA）如何通过符合检测提升对宽带信号的探测能力。研究发现，与仅使用LIGO的网络相比，采用功率循环LIGO和VIRGO，并结合双程循环GEO和AIGO的网络，可将天区覆盖范围提升3.2倍，显著提高对并合双星和突发信号的探测灵敏度与源定位精度。

ABSTRACT

We describe how the six planned detectors (2 LIGOs, VIRGO, GEO, AIGO, TAMA) can be used to perform coincidence experiments for the detection of broadband signals from either coalescing compact binaries or burst sources. We make comparisons of the achievable sensitivities of these detectors under different optical configurations and find that a meaningful coincidence experiment for the detection of coalescing binary signals can only be performed by a network where the LIGOs and VIRGO are operated in power recycling mode and other medium scale detectors are operated in dual recycling mode. For the model of burst waveform considered by us (i.e. uniform power upto 2000Hz), we find that the relative sensitivity of the power-recycled VIRGO is quite high as compared to others with their present design parameters and thus coincidence experiment performed by including VIRGO in the network would not be a meaningful one. We also calculate optimized values for the time-delay window sizes for different possible networks. The effect of filtering on the calculation of thresholds has also been discussed. We set the thresholds for different detectors and find out the volume of sky that can be covered by different possible networks and the corresponding rate of detection of coalescing binaries in the beginning of the next century. We note that a coincidence experiment of power-recycled LIGOs and VIRGO and dual-recycled GEO and AIGO can increase the volume of the sky covered by 3.2 times as compared with only the power-recycled LIGO detectors and by 1.7 times the sky covered by the power-recycled LIGO-VIRGO network. These values are far less than the range that can be covered by only the LIGO-VIRGO network with dual recycling operation at a later stage, but the accuracy in the determination of direction, distance and other source parameters will be much

研究动机与目标

• 评估多探测器网络在探测来自并合致密双星和突发源的宽带引力波信号方面的有效性。
• 在实际设计参数下，比较不同探测器配置（特别是功率循环模式与双程循环模式）的灵敏度差异。
• 确定不同网络组合下符合检测的最佳时间延迟窗口大小。
• 量化在结合具有不同光学配置的探测器时，对并合双星的天区覆盖范围和探测率的提升程度。
• 评估滤波和阈值设置对探测性能及源参数估计精度的影响。

提出的方法

• 使用匹配滤波技术，对干涉探测器中宽带信号的信噪比（SNR）进行建模。
• 在不同光学配置（功率循环与双程循环）下，计算每个探测器（LIGO、VIRGO、GEO、AIGO、TAMA）的相对灵敏度。
• 基于检测间的时间延迟，为每种网络配置定义符合窗口，并进行优化。
• 应用滤波技术以降低误报率，并优化符合触发的阈值选择。
• 利用几何与统计模型，估算每种网络配置可监测的有效天区体积。
• 使用蒙特卡洛模拟，基于网络灵敏度与天区覆盖范围，估算2000年代初并合双星的探测率。

实验结果

研究问题

• RQ1 哪种探测器光学配置组合能最大化对宽带引力波信号探测的灵敏度？
• RQ2 在功率循环模式下，VIRGO的加入如何影响网络的整体探测性能，尤其是其影响机制？
• RQ3 不同探测器网络配置下，符合检测的最佳时间延迟窗口大小是多少？
• RQ4 滤波如何影响符合检测方案中的阈值设定与误报率？
• RQ5 与单探测器或双探测器设置相比，多探测器网络在天区覆盖范围和探测率方面提升了多少倍？

主要发现

• 将功率循环的LIGO和VIRGO与双程循环的GEO和AIGO组合的网络，相比仅使用功率循环LIGO的网络，可将可观测天区体积提升3.2倍。
• 在当前设计参数下，功率循环的VIRGO配置表现出显著高于其他探测器的相对灵敏度，因此在有意义的符合检测中效果较差。
• 若在后期阶段使LIGO-VIRGO网络采用双程循环运行，其可覆盖的天区体积将远大于当前配置，尽管本研究尚未实现该情况。
• 在包含功率循环LIGO和VIRGO的网络中引入双程循环的GEO和AIGO，可显著提高源定位精度与探测置信度。
• 优化后的时间延迟窗口大小因网络配置而异，低灵敏度探测器需要更大的窗口以维持符合效率。
• 随着网络规模扩大，并合双星的探测率显著提升，尤其是当结合具有互补灵敏度与几何布局的探测器时。