本文研究离散源散粒噪声与星系成团导致的非Poisson源分布两类源各向异性,量化其对PTA中Hellings and Downs相关性均值和方差的影响,发现散粒噪声效应远强于成团效应。
摘要:
脉冲星计时阵列(PTA)通过寻找引力波(GW)在不同脉冲星到达时间残差中诱发的相关性来搜寻引力波。如果引力波源具有天体物理起源,那么它们位于天空中的离散点上。然而,PTA数据通常通过“标准高斯系综”进行建模并随后加以分析。该系综是在无限密度、强度趋于零且服从Poisson分布的源的极限下得到的。在本文中,我们脱离该系综,研究两类“源各向异性”的效应。第一类(a)通常被称为“散粒噪声”,其产生原因是在特定天空位置存在N个离散引力波源。第二类(b)的产生原因是引力波源位置并非Poisson过程,例如,星系位置存在成团性。在这里,我们量化(a)和(b)对脉冲星平均的Hellings and Downs相关性的均值和方差的影响。对于常规PTA源,我们证明散粒噪声(a)的效应远大于成团性(b)的效应。
英文摘要:
Pulsar timing arrays (PTA) hunt for gravitational waves (GW) by searching for the correlations that GWs induce in the time-of-arrival residuals from different pulsars. If the GW sources are of astrophysical origin, then they are located at discrete points on the sky. However, PTA data are often modeled, and subsequently analyzed, via a "standard Gaussian ensemble". That ensemble is obtained in the limit of an infinite density of vanishingly weak, Poisson-distributed sources. In this paper, we move away from that ensemble, to study the effects of two types of "source anisotropy". The first (a), which is often called "shot noise", arises because there are $N$ discrete GW sources at specific sky locations. The second (b) arises because the GW source positions are not a Poisson process, for example, because galaxy locations are clustered. Here, we quantify the impact of (a) and (b) on the mean and variance of the pulsar-averaged Hellings and Downs correlation. For conventional PTA sources, we show that the effects of shot noise (a) are much larger than the effects of clustering (b).
Analytical Estimates of Gravitational Wave Background Anisotropies from Shot Noise and Large-Scale Structure in Pulsar Timing Arrays
Simon Fraser University(西蒙菲莎大学);Canadian Institute for Theoretical Astrophysics (CITA), University of Toronto(多伦多大学理论天体物理研究所 (CITA));University of Pennsylvania(宾夕法尼亚大学);University of California, Berkeley(加州大学伯克利分校)
Pulsar timing array signals induced by black hole binaries in relativistic eccentric orbits
非圆轨道上的单个超大质量黑洞双星可能是快速成熟的脉冲星定时阵列实验的纳赫兹引力波源。我们发展了一种精确有效的方法来计算脉冲星定时阵列信号,由于引力波从吸入相对论偏心轨道的超大质量黑洞双星。我们的方法采用开普勒型参数解模型的第三后牛顿精确进动偏心轨道,而一个新的半解析处方提供了模型的四极阶引力波发射的影响。这些输入导致一个半解析的处方来模拟这样的信号,引起的非自旋黑洞二进制沿任意偏心率轨道螺旋。此外,我们提供了一个完整的分析处方模型脉冲星定时阵列信号从黑洞二进制沿适度偏心轨道吸气,Boetzelet等人的影响。[Phys. Rev. D 96,044011(2017)]。这些方法正在被纳入企业和TEMPO 2搜索脉冲星定时阵列数据集中存在这样的二进制文件。
Non-Gaussian timing residual skewness in pulsar timing arrays
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Leibnitz Universität Hannover(马克斯·普朗克引力物理研究所(爱因斯坦研究所),莱布尼茨汉诺威大学);Department of Physics, National Central University(国立中央大学物理系);Institute of Physics, Academia Sinica(台湾中央研究院物理研究所);Institute of Astronomy and Astrophysics, Academia Sinica(台湾中央研究院天文及天文物理研究所)
Detecting Chiral Gravitational Wave Background with a Dipole Pulsar Timing Array
National Astronomical Observatories, Chinese Academy of Sciences(中国科学院国家天文台);Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences(中国科学院大学杭州高等研究院);School of Astronomy and Space Science, University of Chinese Academy of Sciences(中国科学院大学天文与空间科学学院);Institute of Fundamental Physics and Quantum Technology, Ningbo University(宁波大学基础物理与量子技术研究所);Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo(东京大学宇宙木理论研究所);Asia Pacific Center for Theoretical Physics(亚太理论物理中心);Leung Center for Cosmology and Particle Astrophysics, National Taiwan University(台湾大学梁氏宇宙学与粒子天体物理学研究中心);Yukawa Institute for Theoretical Physics, Kyoto University(京都大学汤川理论物理研究所)
Why Gravitational Wave Science Needs Pulsar Timing Arrays And Why Pulsar Timing Arrays Need Both Arecibo and the GBT: A Response to the NSF-AST Portfolio Review from the NANOGrav Collaboration
CENTRA, Departamento de Física, Instituto Superior Técnico – IST Universidade de Lisboa – UL(里斯本大学高级技术学院物理系中心);Departamento de Física Fundamental, Universidad de Salamanca(萨拉曼卡大学基础物理系);Insituto Universitario de Física Fundamental y Matemáticas (IUFFyM), Universidad de Salamanca(萨拉曼卡大学基础物理与数学大学研究所)
Millisecond and Binary Pulsars as Nature's Frequency Standards. III. Fourier Analysis and Spectral Sensitivity of Timing Observations to Low-Frequency Noise
Searching for gravitational waves from the Crab pulsar - the problem of timing noise
蟹状星云脉冲星(B 0531 +21)是目前已知的最有希望的引力波源之一。蟹状星云相对较大的定时噪声导致其相位演化偏离简单的自旋下降模型。在对蟹状星云脉冲星进行时域搜索时,需要考虑这种影响,以避免搜索效率的严重下降。Jodrell Bank Crab脉冲星星历表的检查,看看它是否可以用于跟踪相位演化的任何引力波信号从脉冲星,我们提出了一种外差的数据,考虑到相位漂移的方法。从电磁和引力观测的定时噪声的比较获得有关脉冲星的物理信息的可能性进行了讨论。最后,脉冲星毛刺所造成的其他问题进行了讨论。
A Realistic Pulsar -- Supermassive Black Hole Timing Model
Peking University(北京大学);Kavli Institute for Astronomy and Astrophysics, Peking University(北京大学科维理天文与天体物理研究所);National Astronomical Observatories, Chinese Academy of Sciences(中国科学院国家天文台)