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arXiv 2606.00577gr-qcastro-ph.COastro-ph.IM
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在脉冲星计时阵列中搜索波形无关的引力波信号

Searching for a waveform-agnostic gravitational wave signal in pulsar timing arrays

Columbia University（哥伦比亚大学）；University of Birmingham（伯明翰大学）；Monash University（蒙纳士大学）；Montana State University（蒙大拿州立大学）；Oregon State University（俄勒冈州立大学）

Heling Deng, Bence Becsy, Yuri Levin, Neil J. Cornish, Xavier Siemens

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16 pages, 16 figures
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AI总结：

提出一种基于傅里叶展开的波形无关框架，通过贝叶斯层次模型同时推断引力波源的天区位置、频率成分和随机背景，为脉冲星计时阵列提供灵活且鲁棒的信号搜索工具。

摘要：

脉冲星计时阵列最近提供了纳赫兹随机引力波背景的有力证据，激发了对来自局部源的引力波的搜索。大多数现有搜索假设特定的波形模板，这可能在计算上要求很高，并且可能对意外信号不敏感。我们引入了一个波形无关的框架，通过傅里叶展开对信号引起的计时残差进行建模。对傅里叶系数的方差施加洛伦兹超先验，提供了一个灵活的频谱包络，捕获信号的主频和带宽，同时对其精确形状保持无关。然后，对傅里叶系数进行解析边缘化，得到一个贝叶斯层次框架，同时推断源的天区位置、频率内容和随机背景。为了减轻未建模的脉冲星噪声的污染，我们还允许每颗脉冲星具有额外的平谱特征。在模拟数据集上的测试表明，该方法具有鲁棒性，并为未来的PTA搜索提供了灵活的工具，对预期和意外的引力波现象都具有敏感性。

英文摘要：

Pulsar timing arrays have recently provided compelling evidence for a nanohertz stochastic gravitational wave background, motivating searches for gravitational waves from localized sources. Most existing searches assume specific waveform templates, which can be computationally demanding and potentially insensitive to unexpected signals. We introduce a waveform-agnostic framework that models signal-induced timing residuals via a Fourier expansion. A Lorentzian hyperprior is imposed on the variances of the Fourier coefficients, providing a flexible spectral envelope that captures the signal's dominant frequency and bandwidth while remaining agnostic to its exact shape. Analytical marginalization over the Fourier coefficients then yields a Bayesian hierarchical framework that concurrently infers the source sky location, its frequency content, and the stochastic background. To mitigate contamination from unmodeled pulsar noise, we further allow for additional flat-spectrum features for each pulsar. Tests on simulated datasets show that the method is robust and provides a flexible tool for future PTA searches, with sensitivity to both expected and unexpected gravitational wave phenomena.

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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