Collaborative Proposal: Enhanced Gravitational Wave Search via Simultaneous Advanced LIGO/Virgo and Evryscope Detection

合作提案：通过同时先进的 LIGO/Virgo 和 Evryscope 检测增强引力波搜索

• 批准号: 1806625
• 负责人: Nicholas Law
• 金额: $ 4万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1806625&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Enhanced; Gravitational; Wave

The recent gravitational wave (GW) detection of the first binary neutron star (BNS) merger by the LIGO/Virgo gravitational wave observatories and its associated electromagnetic (EM) counterparts has ushered in a new era of multi-messenger astrophysics. The GW170817 event has inspired a new GW search strategy using simultaneous all-sky optical imaging measurements to provide improved detection confidence as well as source identification/localization. This grant will fund the development and testing of this improved GW search in Advanced LIGO/Virgo (aLIGO/Virgo) operation run 3 (O3), with the potential to substantially increase the number of confirmed GW detections. This will significantly improve the progress of science in the national interest by leveraging the existing investments in gravitational wave and optical observatories to provide an estimated ~25% enhancement in the number of detected systems during O3, and pave the way for future multi-messenger investigations that could potentially quadruple the number of detected sources. The proposed research is at the intersection of the multi-messenger astrophysics, general relativity, digital signal processing and computing, which require young researchers to develop a deep knowledge of modern astrophysical theories, and understanding of gravitational wave instrumentation, and gives them opportunity to get firsthand experience with sophisticated signal/image-processing algorithms, computational methods, manipulation of large data sets and high performance computing.The novel GW search proposed here is based on combining aLIGO/Virgo sub-threshold triggers with simultaneous optical imaging using the Evryscope technique. Evryscope images the entire observable night-time sky simultaneously with 2-minute cadence. Scientists can then select only those optical transient events in the aLIGO/Virgo error region which appear within the same 2-minute window as the GW candidate - reducing the GW-only false alarm probability by factors larger than 20,000. for any night-time GW events. This enables improved detection confidence for marginal GW events and thus enhanced GW detection volume. GW1708187's optical counterpart could be detected by the current Evryscope out to D ~260 Mpc, and future Evryscope-style systems to distances further than 350 Mpc. Analyses show that a future network of Evryscope-style detectors would enhance the number of GW events detected by a factor of ~2-4 compared to GW-only observations. Such a future network would particularly benefit GW source population studies and cosmological applications of GW events. This approach will also provide coverage of the brightest portion of the optical lightcurve, and arcsecond-level localization for all of these events, which will dramatically improve the EM followup response from the community as a whole, leading to improved astrophysical context for interpreting the implications of the GW event. The proposed work here is to carry out a sub-threshold GW search in aLIGO/Virgo O3, using the Evryscope North and South facilities for simultaneous optical coverage. Based on the properties of GW170817's GW properties, optical counterpart, and analyses presented here, such a search could add an additional ~25% more detections to the number of confirmed BNS mergers in O3.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

最近，LIGO/Virgo 引力波天文台及其相关电磁 (EM) 对应物对首个双中子星 (BNS) 合并进行了引力波 (GW) 探测，开创了多信使天体物理学的新时代。 GW170817 事件激发了一种新的引力波搜索策略，该策略使用同步全天光学成像测量来提供更高的检测置信度以及源识别/定位。这笔赠款将资助高级 LIGO/Virgo (aLIGO/Virgo) 运行 3 (O3) 中改进的引力波搜索的开发和测试，有可能大幅增加已确认的引力波探测数量。这将通过利用对引力波和光学天文台的现有投资，使O3期间探测到的系统数量估计增加约25%，从而显着提高符合国家利益的科学进步，并为未来的多信使调查铺平道路，有可能使探测到的源数量增加四倍。拟议的研究处于多信使天体物理学、广义相对论、数字信号处理和计算的交叉点，这要求年轻的研究人员深入了解现代天体物理学理论和对引力波仪器的理解，并让他们有机会获得复杂的信号/图像处理算法、计算方法、大数据集操作和高性能计算的第一手经验。 这里基于将 aLIGO/Virgo 亚阈值触发器与使用 Evryscope 技术的同步光学成像相结合。 Evryscope 以 2 分钟的节奏同时拍摄整个可观测的夜空。 然后，科学家可以仅选择 aLIGO/Virgo 误差区域中出现在与 GW 候选者相同的 2 分钟窗口内的光学瞬态事件，从而将仅 GW 的误报概率降低超过 20,000 倍。适用于任何夜间 GW 活动。这可以提高边缘 GW 事件的检测置信度，从而提高 GW 检测量。 GW1708187 的光学对应物可以被当前的 Evryscope 检测到 D ~260 Mpc，而未来的 Evryscope 型系统可以检测到距离超过 350 Mpc。分析表明，未来的 Evryscope 型探测器网络将比仅观测到的引力波事件数量增加约 2-4 倍。这样的未来网络将特别有利于引力波源群体研究和引力波事件的宇宙学应用。这种方法还将提供光学光曲线最亮部分的覆盖，以及所有这些事件的弧秒级定位，这将极大地改善整个社区的电磁后续响应，从而改善解释引力波事件影响的天体物理背景。这里提议的工作是在 aLIGO/Virgo O3 中进行亚阈值引力波搜索，使用 Evryscope 南北设施进行同步光学覆盖。根据 GW170817 的 GW 特性、光学对应物的特性以及此处介绍的分析，此类搜索可以使 O3 中已确认的 BNS 合并数量增加约 25%。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。