For the first time we analyze gravitational-wave strain data using waveforms constructed from strong gravity simulations of cosmic string loops collapsing to Schwarzschild black holes; a previously unconsidered source. Since the expected signal is dominated by a black-hole ringdown, it can mimic the observed gravitational waves from high-mass binary black hole mergers. To illustrate this, we consider GW190521, a short duration gravitational-wave event observed in the third LIGO-Virgo-KAGRA observing run. We show that describing this event as a collapsing cosmic string loop is favored over previous cosmic string analyses by an approximate log Bayes factor of 22. The binary black hole hypothesis is still preferred, mostly because the cosmic string remnant is nonspinning. It remains an open question whether a spinning remnant could form from loops with angular momentum, but if possible, it would likely bring into contention the binary black hole preference. Finally, we suggest that searches for ringdown-only waveforms would be a viable approach for identifying collapsing cosmic string events and estimating their event rate. This Letter opens up an important new direction for the cosmic-string and gravitational-wave communities.

中文翻译：

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重温GW190521的宇宙弦起源

我们首次使用从坍缩成史瓦西黑洞的宇宙弦环的强引力模拟构建的波形来分析引力波应变数据；以前未被考虑的来源。由于预期信号主要由黑洞振铃主导，因此它可以模拟从高质量双黑洞合并中观测到的引力波。为了说明这一点，我们考虑 GW190521，这是在第三次 LIGO-Virgo-KAGRA 观测运行中观测到的一个短时引力波事件。我们表明，将这一事件描述为坍缩的宇宙弦环比以前的宇宙弦分析更受青睐，其近似对数贝叶斯因子为 22。二元黑洞假说仍然是首选，主要是因为宇宙弦残余物是不旋转的。旋转残余物是否可以由具有角动量的环形成仍然是一个悬而未决的问题，但如果可能的话，它可能会引起对双黑洞偏好的争论。最后，我们建议搜索仅振铃波形将是识别坍缩宇宙弦事件并估计其事件发生率的可行方法。这封信为宇宙弦和引力波界开辟了一个重要的新方向。