Gravitational Waves at the University of Portsmouth - 24/25

朴茨茅斯大学的引力波 - 24/25

• 批准号: ST/Y005260/1
• 负责人: Ian Harry
• 金额: $ 17.06万
• 依托单位: University of Portsmouth
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FY005260%2F1
• 关键词: Gravitational; Waves; University; Portsmouth; 24

Gravitational waves are one of the most remarkable predictions of Einstein's General Theory of Relativity. These can be thought of as ripples in the fabric of spacetime propagating at the speed of light. Gravitational waves are emitted by non-spherically symmetric accelerated masses, such as two black holes or neutron stars orbiting each other. Gravitational waves are incredibly difficult to detect, but in the last years large-scale observatories, including Advanced LIGO, Advanced Virgo and KAGRA, have reached the necessary sensitivity to observe gravitational waves.The first gravitational-wave signal observed in September 2015 was produced by two black holes roughly 35 times the mass of our Sun colliding approximately one billion light years away. Since then twelve additional binary black hole mergers have been observed. The crowning achievement of gravitational-wave astronomy to date was the observation of two merging neutron stars in August 2017. This signal was special because it was observed simultaneously as a gamma-ray burst by the Fermi observatory and then, following the release of the gravitational-wave sky localisation region to astronomers, was observed across the electromagnetic spectrum.The potential of "multi-messenger" astronomy (observing sources with multiple "messengers", such as gravitational-waves, photons, neutrinos or cosmic rays) is remarkable. We can explore the validity of Einstein's theory in one of the most extreme environments possible. We can make an independent measurement of the rate at which the Universe is accelerating. We can probe the nature of matter deep within a neutron star, where it is so dense that 1 teaspoon of material weighs as much as a mountain on the Earth.However, all of this requires us to actually observe these gravitational-wave signals, reliably estimate their source parameters and to do it quickly enough that we can alert astronomers to search for a coincident signal. In this grant we will develop methods to promptly search data from Advanced LIGO, Advanced Virgo and KAGRA to observe the gravitational-wave signature of merging compact objects. We will ensure that such observations are rapidly localised on the sky and that this information is rapidly communicated to astronomers. We will also develop techniques to further improve the sensitivity of these searches, allowing us to dig deeper into the noise, and to observe new types of compact binary mergers that have not been observed to date.We will also work to better understand the data that is produced by the LIGO observatories. These gravitational-wave observatories are highly precise and complex machines and producing a "clean" data stream free of instrumental noise is a significant challenge. We will work in collaboration with the instrument scientists at the LIGO sites to "characterise" the data being recorded by these instruments. This will allow us to identify the causes of any "imperfections" in the data stream. These imperfections, which often show up as bangs and whistles in the data, harm our ability to observe genuine astrophysical signals. Additionally, if we do not include the effects of noisy data when assessing the parameters of sources that we observe, we run the risk of quoting incorrect, or biased, parameters for our observations. By identifying the causes of such signals we can fix the instrument to stop them happening. We can also understand the effect that these bangs and whistles will have on our ability to understand our new observations. This problem is illustrated in the online project Gravity Spy. If interested, you can visit the Gravity Spy website and help us in this effort!

引力波是爱因斯坦广义相对论最引人注目的预言之一。这些可以被认为是时空结构中以光速传播的涟漪。引力波是由非球对称加速质量发射的，例如两个黑洞或彼此绕轨道运行的中子星。引力波极其难以探测，但在过去几年中，包括 Advanced LIGO、Advanced Virgo 和 KAGRA 在内的大型天文台已经达到了观测引力波所需的灵敏度。2015 年 9 月观测到的第一个引力波信号是由两个质量约为太阳质量 35 倍的黑洞在大约 10 亿光年之外相撞。从那时起，又观测到了十二次双黑洞合并。迄今为止，引力波天文学的最高成就是 2017 年 8 月观测到两颗合并的中子星。这个信号很特别，因为费米天文台同时观测到它是伽马射线暴，然后在引力波释放后-天文学家在整个电磁频谱中观察到波天空定位区域。“多信使”天文学的潜力（观测具有多个“信使”的源，例如引力波、光子、中微子或宇宙射线）是引人注目的。我们可以在最极端的环境之一中探索爱因斯坦理论的有效性。我们可以对宇宙加速的速度进行独立测量。我们可以探测中子星深处物质的本质，那里的密度非常大，一茶匙物质的重量相当于地球上一座山的重量。然而，所有这一切都需要我们可靠地实际观测这些引力波信号估计它们的源参数并足够快地完成，以便我们可以提醒天文学家寻找一致的信号。在这笔赠款中，我们将开发方法来快速搜索来自 Advanced LIGO、Advanced Virgo 和 KAGRA 的数据，以观察合并致密天体的引力波特征。我们将确保此类观测迅速在天空中定位，并将这些信息迅速传达给天文学家。我们还将开发技术来进一步提高这些搜索的灵敏度，使我们能够更深入地挖掘噪音，并观察迄今为止尚未观察到的新型紧凑二元合并。我们还将努力更好地理解这些数据由 LIGO 天文台制作。这些引力波天文台是高度精确且复杂的机器，产生没有仪器噪声的“干净”数据流是一项重大挑战。我们将与 LIGO 站点的仪器科学家合作，“表征”这些仪器记录的数据。这将使我们能够识别数据流中任何“缺陷”的原因。这些缺陷通常在数据中表现为爆炸声和口哨声，损害了我们观察真实天体物理信号的能力。此外，如果我们在评估我们观察到的来源参数时不包括噪声数据的影响，我们就有可能为我们的观察引用不正确或有偏见的参数。通过确定此类信号的原因，我们可以修复仪器以阻止它们发生。我们还可以理解这些爆炸声和口哨声将对我们理解新观察结果的能力产生影响。这个问题在在线项目 Gravity Spy 中得到了说明。如果有兴趣，您可以访问 Gravity Spy 网站并帮助我们完成这项工作！