Astrophysics Milestones for Pulsar Timing Array Gravitational-wave Detection-猫眼课题宝

DOI：

10.3847/2041-8213/abf2c9

发表时间：

2020-10

期刊：

The Astrophysical Journal Letters

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

N. Pol;S. Taylor;Luke Zoltan Kelley;S. Vigeland;J. Simon;Siyuan Chen;Z. Arzoumanian;P. Baker;B. Bécsy;A. Brazier;P. Brook;S. Burke-Spolaor;S. Chatterjee;J. Cordes;N. Cornish;F. Crawford;H. Thankful Cromartie;M. DeCesar;P. Demorest;T. Dolch;E. Ferrara;W. Fiore;E. Fonseca;N. Garver-Daniels;D. Good;J. Hazboun;R. Jennings;Megan L. Jones;A. Kaiser;D. Kaplan;Joey Shapiro Key;M. Lam;T. Lazio;Jing Luo;R. Lynch;D. Madison;A. McEwen;M. Mclaughlin;C. Mingarelli;C. Ng;D. Nice;T. Pennucci;S. Ransom;P. Ray;B. Shapiro-Albert;X. Siemens;I. Stairs;D. Stinebring;J. Swiggum;M. Vallisneri;H. Wahl;C. Witt

NANOGrav的合作报告了在其12.5年脉冲星计时阵列数据集中存在共谱随机过程的强有力的贝叶斯证据，其特征应变幅度的中值为一年的周期。然而，作为引力波信号特征的四极Hellings&Down脉冲星间关联的证据还不明显。我们模拟和扩展了NANOGrav数据集，注入了广泛的随机引力波背景(GWB)信号，包括各种幅度和频谱形状，并量化了三个关键里程碑。(I)鉴于在12.5年分析中测量的幅度，并假设该信号是GWB，我们预计将积累具有15-17年数据的脉间相关GWB信号的可靠证据，即从12.5年数据集中额外获得2-5年数据。(Ii)在初始探测时，我们预计幂定律应变谱斜率的分数不确定度为40%，这足以区分超大质量黑洞双星起源的GWB和一些预测更奇异起源的模型。(Iii)类似地，测量的GWB振幅在最初探测时将具有44%的不确定度，这允许我们在一些超大质量黑洞双星的群数模型之间进行仲裁。此外，一旦获得20年的数据，幂定律模型与那些具有低频频谱转换的模型是可以区分的。即使我们的研究是基于NANOGrav数据，我们也推导出了允许推广到其他脉冲星定时阵列数据集的关系。最值得注意的是，通过将单个阵列的数据合并到国际脉冲星定时阵列中，所有这些里程碑都可以显著提前实现。

The NANOGrav Collaboration reported strong Bayesian evidence for a common-spectrum stochastic process in its 12.5 yr pulsar timing array data set, with median characteristic strain amplitude at periods of a year of . However, evidence for the quadrupolar Hellings & Downs interpulsar correlations, which are characteristic of gravitational-wave signals, was not yet significant. We emulate and extend the NANOGrav data set, injecting a wide range of stochastic gravitational-wave background (GWB) signals that encompass a variety of amplitudes and spectral shapes, and quantify three key milestones. (I) Given the amplitude measured in the 12.5 yr analysis and assuming this signal is a GWB, we expect to accumulate robust evidence of an interpulsar-correlated GWB signal with 15–17 yr of data, i.e., an additional 2–5 yr from the 12.5 yr data set. (II) At the initial detection, we expect a fractional uncertainty of 40% on the power-law strain spectrum slope, which is sufficient to distinguish a GWB of supermassive black hole binary origin from some models predicting more exotic origins. (III) Similarly, the measured GWB amplitude will have an uncertainty of 44% upon initial detection, allowing us to arbitrate between some population models of supermassive black hole binaries. In addition, power-law models are distinguishable from those having low-frequency spectral turnovers once 20 yr of data are reached. Even though our study is based on the NANOGrav data, we also derive relations that allow for a generalization to other pulsar timing array data sets. Most notably, by combining the data of individual arrays into the International Pulsar Timing Array, all of these milestones can be reached significantly earlier.

Astrophysics Milestones for Pulsar Timing Array Gravitational-wave Detection

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