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arXiv 2406.16031gr-qcastro-ph.COastro-ph.GA
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源各向异性与脉冲星计时阵列

Source anisotropies and pulsar timing arrays

Bruce Allen, Deepali Agarwal, Joseph D. Romano, Serena Valtolina

AI总结:

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).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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