论文标题
外来紧凑物体的回声有多大声？
How loud are echoes from exotic compact objects?
论文作者
论文摘要
LIGO协作对重力波（GWS）的首次直接观察已经激发了一般相对性（GR）的不同测试，包括在紧凑型物体合并的GR波形之后搜索额外的脉冲。这些搜索的动机来自替代提议，即最终紧凑的物体可能因缺乏事件范围和中心奇异性而与黑洞（BH）有所不同。在理论中期望这样的物体，这些理论是由量子重力修改的动机，将无层的物体预测为重力崩溃的最后阶段。在这种假设的情况下，这种异国情调的紧凑对象（ECO）将在$ r _ {\ rm eco} = r _ {+}（1+ε）$的情况下（部分）反射表面，而不是$ r _ {+} $的事件地平线。对于这类对象，活动中的浪潮不会完全丢失，并且会引起次要脉冲，最近的文献将其称为回声。但是，在很大程度上未知的生态反射率是信号振幅的决定因素，细节还取决于祖细胞紧凑型二元的初始条件。在这里，我们首次使用Inspiral-Merger-Ringdown波形和物理动机的ECO反射率的扰动描述获得了第一个回声的可检测性的估计。具有可比质量的二进制文件将具有更强的第一回声，从而提高了检测的机会。对于GW150914之类的情况，对第一个回声的检测将需要在$ \ sim 20-60 $范围内的最小响声信号比率（SNR）。在接下来的几年中，Ligo已经可以探究最乐观的回声检测场景。随着灵敏度的预期提高，我们每年估计一两个事件在O4期间具有首次回声检测所需的SNR。
The first direct observations of gravitational waves (GWs) by the LIGO collaboration have motivated different tests of General Relativity (GR), including the search for extra pulses following the GR waveform for the coalescence of compact objects. The motivation for these searches comes from the alternative proposal that the final compact object could differ from a black hole (BH) by the lack of an event horizon and a central singularity. Such objects are expected in theories that, motivated by quantum gravity modifications, predict horizonless objects as the final stage of gravitational collapse. In such a hypothetical case, this exotic compact object (ECO) will present a (partially) reflective surface at $r_{\rm ECO}=r_{+}(1+ε)$, instead of an event horizon at $r_{+}$. For this class of objects, an in-falling wave will not be completely lost and will give rise to secondary pulses, to which recent literature refers as echoes. However, the largely unknown ECO reflectivity is determinant for the amplitude of the signal, and details also depend on the initial conditions of the progenitor compact binary. Here, for the first time, we obtain estimates for the detectability of the first echo, using a perturbative description for the inspiral-merger-ringdown waveform and a physically-motivated ECO reflectivity. Binaries with comparable masses will have a stronger first echo, improving the chances of detection. For a case like GW150914, the detection of the first echo will require a minimum ringdown signal-to-noise ratio (SNR) in the range $\sim 20-60$. The most optimistic scenario for echo detection could already be probed by LIGO in the next years. With the expected improvements in sensitivity we estimate one or two events per year to have the required SNR for the first echo detection during O4.
