Searches for Gravitational Wave Transients: Data Analysis for Advanced LIGO

引力波是时空结构中的涟漪，由移动的质量以光速在宇宙中传播。阿尔伯特·爱因斯坦1915年的广义相对论预言，引力波在长达一百年的时间里一直没有被探测到，直到2015年9月14日，也就是重大升级后不久，先进的LIGO探测器观测到了来自两个碰撞黑洞的引力波信号。LIGO第一次探测到来自遥远宇宙的灾难性事件到达地球的时空结构中的涟漪。这证实了广义相对论的一个重大预言，并打开了一扇前所未有的了解宇宙的新窗口。引力波提供了对复杂天体物理系统的直接探测，并为研究宇宙提供了独特的天文工具。在接下来的几年里，随着先进的LIGO达到其设计灵敏度，以及其他仪器加入全球引力波探测器网络，预计将有数百个源探测到。这些探测器的实验将解决关键研究问题，包括黑洞和中子星的形成和演化，致密天体在高能发射中的作用，核物质的性质，伽马射线爆发的性质，以及中等质量黑洞的存在，探索宇宙的结构和演化，以及超越广义相对论的物理学。拟议的研究将加强LIGO数据分析工作的成功，并支持有可能产生变革性结果的新的创新研究项目。它的目标是最极端的天体物理事件，如最近发现的中子星和黑洞的合并，并有望发现全新的天体物理现象。拟议的搜索利用检测和重建算法，这些算法使用最小的模型假设，并能够在广泛的震源参数范围内检测引力波瞬变，包括尚不清楚的震源。核心塌缩超新星(CCSN)是主要的探测目标之一，它将解决天体物理学中的一些悬而未决的问题，如中微子在CCSN中的作用和中子星状态方程。此外，建议的活动还将把最有希望的高级LIGO搜索扩展到现有模板算法尚未探索的二元参数空间。通过将重建的信号波形与数值相对论预测进行比较，所提出的搜索有可能确定中等质量双黑洞的存在，并在高场区域检验广义相对论。提出了研究紧凑的双星合并后信号的新方法，包括残余黑洞发出的准正常引力波和双星中子星系统合并后的特征。快速的源重建和天空定位将使与电磁望远镜和中微子探测器的联合观测成为可能，推动多信使天文学领域的发展。该奖项还将支持为未来的LIGO运行升级基线LIGO数据分析算法的计划，并增加拟议的引力波观测的科学潜力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Gravitational waves are the ripples in the fabric of space-time created by moving masses, which travel through the universe at the speed of light. Predicted by Albert Einstein's 1915 theory of General Relativity, gravitational waves eluded detection for a hundred years, until on September 14, 2015, shortly after the major upgrade, the advanced LIGO detectors observed a gravitational wave signal from two colliding black holes. For the first time, LIGO detected ripples in the fabric of space-time arriving at the Earth from a cataclysmic event in the distant universe. This confirmed a major prediction of General Relativity and opened an unprecedented new window onto the cosmos. Gravitational-waves provide a direct probe of complex astrophysical systems and provide a unique astronomical tool to study the Universe. In the next few years hundreds detections of sources are expected as advanced LIGO reaches its design sensitivity and the other instruments join the world-wide network of gravitational wave detectors. The experiments with these detectors will address key research questions, including the formation and evolution of black holes and neutron stars, the role of compact objects in high energy emission, the properties of nuclear matter, the nature of gamma-ray-bursts, and the existence of intermediate-mass black holes, probing the structure and evolution of the Universe and physics beyond General Relativity.The proposed research will reinforce success of the LIGO data analysis effort and support new innovative research projects that have a potential to produce transformative results. It targets the most extreme astrophysical events, such as recently discovered mergers of neutron stars and black holes, and holds a promise for discoveries of entirely new astrophysical phenomena. The proposed searches utilize the detection and reconstruction algorithms that use minimal model assumptions and that are capable of detecting gravitational-wave transients in a wide range of source parameters, including yet unknown sources. Among the primary detection targets is a core collapse supernovae (CCSN), which will address a number of open questions in astrophysics, such as the role of neutrino in CCSN and the neutron star equations of state. Also, the proposed activities will extend the most promising advanced LIGO searches for compact binary sources into the binary parameter space not yet explored by the existing template algorithms. The proposed searches have a potential to establish the existence of intermediate mass binary black holes and test the theory of general relativity at the high field regime by comparing the reconstructed signal waveforms with the numerical relativity predictions. Novel methods are proposed for studies of the compact binary post-merger signals, including quasi-normal gravitational waves emitted by the remnant black holes and post-merger signatures of the binary neutron star systems. Rapid source reconstruction and sky localization will enable joint observations with the electromagnetic telescopes and neutrino detectors, advancing the field of the multi-messenger astronomy. This award will also support the planned upgrade of the baseline LIGO data analysis algorithms for the future LIGO runs and increase the scientific potential of the proposed gravitational-wave observations.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.