In a binary black hole merger, it is known that the inspiral portion of the waveform corresponds to two distinct horizons orbiting each other and that the merger and ringdown signals correspond to the final horizon being formed and settling down to equilibrium. However, we still lack a detailed understanding of the relation between the horizon geometry in these three regimes and the observed waveform. Here we show that the well-known inspiral chirp waveform has a clear counterpart on black hole horizons, namely, the shear of the outgoing null rays at the horizon. We demonstrate that the shear behaves very much like a compact binary coalescence waveform with increasing frequency and amplitude. Furthermore, the parameters of the system estimated from the horizon agree with those estimated from the waveform. This implies that even though black hole horizons are causally disconnected from us, assuming general relativity to be true, we can potentially infer some of their detailed properties from gravitational wave observations.

中文翻译：

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Horizo​​ns在二进制黑洞合并中的新闻

在二进制黑洞合并中，已知波形的吸气部分对应于彼此绕行的两个不同的层位，并且合并和振铃信号对应于正在形成并稳定下来的最终层位。但是，我们仍然缺乏对这三种情况下视界几何形状与观测波形之间关系的详细了解。在这里，我们显示了著名的吸气chi声波形在黑洞视界上具有明显的对应关系，即，在视界处的出射空光线的切变。我们证明，剪切的行为非常像具有增加的频率和幅度的紧凑的二进制合并波形。此外，从水平线估计的系统参数与从波形估计的参数一致。