Searching for Long-Lasting Gravitational-Wave Signals with Second-Generation Gravitational-Wave Detectors

用第二代引力波探测器寻找持久的引力波信号

• 批准号: 1204944
• 负责人: Vuk Mandic
• 金额: $ 36万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-15 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1204944&HistoricalAwards=false
• 关键词: Searching; Long; Lasting; Gravitational; Wave

Predicted by Einstein's Theory of General Relativity, gravitational waves have evaded direct detection for nearly a century due to their exquisitely small amplitudes. However, with the arrival of the second-generation gravitational-wave detectors, such as Advanced LIGO and Advanced Virgo, first detections of gravitational waves produced in astrophysical and cosmological processes are expected to be made over the next decade. This project focuses on gravitational waves emitted on long time scales, such as the stationary stochastic gravitational-wave background (SGWB) generated by an incoherent superposition of signals from many independent sources. The project also targets transient gravitational-wave signals on the time-scales of minutes, hours or longer, generated by a variety of astrophysical processes such as dynamically formed black-hole binaries or fragmentation in accretion disks around black holes. Cross-correlation techniques will be applied to the first data to be acquired by the second-generation detectors in search for these long-lasting signals. With over 1000 times better sensitivity than the latest published results, these searches will probe and constrain a number of proposed SGWB models. Furthermore, the SGWB models will be systematically studied to precisely identify the open science questions within these models that could be pursued by the second-generation detectors. Examples of such open questions include: What is the equation of state in neutron stars? What is the coalescence rate of binary neutron stars? Which cosmological models of SGWB are accessible to the second-generation detectors?This project is expected to have a strong impact on cosmology and astrophysics. For example, the SGWB is expected to be generated just moments after the Big Bang, and hence may contain unique information about the first moments in the evolution of the universe and about the physics of highest energy scales, which is otherwise not accessible in laboratories. Similarly, the SGWB could be of astrophysical origin: for example, summing up contributions from all binary neutron stars, binary black holes, magnetars, or Supernovae in the universe leads to a stochastic gravitational-wave "foreground" that contains information about these most violent objects and events in the universe. The long-lasting transient gravitational-wave signals will also provide information about the astrophysical objects and processes that generated them. For example, direct detection of gravitational-wave signals produced by dynamically formed black hole binaries would shed light on the population of black holes that lurk in the inner regions of nearby galaxies, revealing their density and velocity distribution.

根据爱因斯坦广义相对论的预测，引力波由于其极其微小的振幅，在近一个世纪的时间里一直未能被直接探测到。然而，随着第二代引力波探测器（例如 Advanced LIGO 和 Advanced Virgo）的到来，预计将在未来十年内首次探测到天体物理和宇宙学过程中产生的引力波。该项目重点研究长时间尺度上发射的引力波，例如由许多独立来源的信号不相干叠加产生的静止随机引力波背景（SGWB）。该项目还针对由各种天体物理过程产生的分钟、小时或更长时间的瞬态引力波信号，例如动态形成的黑洞双星或黑洞周围吸积盘的碎片。互相关技术将应用于第二代探测器采集的第一批数据，以寻找这些持久的信号。这些搜索的灵敏度比最新发布的结果高出 1000 倍以上，将探测和约束许多拟议的 SGWB 模型。此外，还将系统地研究 SGWB 模型，以精确识别这些模型中第二代探测器可以解决的开放科学问题。此类开放性问题的例子包括：中子星的状态方程是什么？双中子星的聚结率是多少？第二代探测器可以访问哪些SGWB宇宙学模型？该项目预计将对宇宙学和天体物理学产生重大影响。例如，SGWB 预计将在大爆炸后不久生成，因此可能包含有关宇宙演化的第一时刻和最高能量尺度的物理的独特信息，否则这些信息在实验室中无法获得。类似地，SGWB 可能具有天体物理学起源：例如，将宇宙中所有双中子星、双黑洞、磁星或超新星的贡献相加，就会得到一个随机引力波“前景”，其中包含有关这些最暴力的信息。宇宙中的物体和事件。持久的瞬态引力波信号还将提供有关天体物理物体及其产生过程的信息。例如，直接探测动态形成的黑洞双星产生的引力波信号将揭示潜伏在附近星系内部区域的黑洞数量，揭示它们的密度和速度分布。