论文标题

重建引力波信号的非正交小波转换

Nonorthogonal wavelet transformation for reconstructing gravitational wave signals

论文作者

Roy, Soumen

论文摘要

从紧凑的二元融合中检测引力波信号使我们能够研究极端的天体物理现象并探索基本物理学。这些研究的至关重要的必要条件是具有具有特征形态的准确信号模型,数十年来一直具有挑战性,研究人员仍在努力纳入重要的物理学。因此,已经开发了与形态无关的方法来识别信号及其重建。重建的信号使我们能够从参数估计中测试观察到的信号与波形后样品之间的一致性。这些方法模型在连续小波转换框架中使用近几个正交小波的基础观察了信号。在这里,我们提出了对数均匀的尺度来构建小波,与传统的八度尺度相比,它们是高度冗余(非正交)的,但在高频处重建信号的效率更高。我们使用事件的后样品引入了一种半模型依赖性重建方法,在该方法中,我们使用具有对数均匀尺度的Gabor-Morlet小波对信号进行建模。我们证明了使用偏心二进制黑洞合并的数值模拟检测偏差的能力,其中数据中的信号不属于搜索模板波形歧管。最后,我们将此方法应用于GWTC-1中的每个二进制黑洞合并事件。我们发现,GW150914事件产生的信号与波形后验样品的一致96%。随着检测器敏感性的提高,黑洞合并的检测群体的增长,我们预计所提出的方法将提供更强的测试。

Detections of gravitational-wave signals from compact binary coalescences have enabled us to study extreme astrophysical phenomena and explore fundamental physics. A crucial requisite for these studies is to have accurate signal models with characteristic morphologies, which have been challenging for many decades, and researchers are still endeavoring to incorporate important physics. Therefore, morphology-independent methods have been developed for identifying a signal and its reconstruction. The reconstructed signal allows us to test the agreement between the observed signal and the waveform posterior samples from parameter estimation. These methods model observed signals using a nearly orthogonal wavelet basis in the frame of continuous wavelet transformation. Here, we propose log-uniform scales to construct the wavelets, which are are highly redundant (nonorthogonal) compared to the conventional octave scales but more efficient for reconstructing the signals at high frequencies. And we introduce a semi-model-dependent reconstruction method using the posterior samples of the events, where we model the signal using Gabor-Morlet wavelets with log-uniform scales. We demonstrate the ability to detect deviation using a numerical simulation of an eccentric binary black hole merger, where the signal in the data does not belong to the search template waveform manifold. Finally, we apply this method to each binary black hole merger event in GWTC-1. We have found that the signal produced by the GW150914 event has 96% agreement with the waveform posterior samples. As the detector sensitivity improves and the detected population of black hole mergers grows, we expect the proposed method will provide even stronger tests.

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