Title: Gravitational waves from a plunge into a nearly extremal Kerr black hole Show Chinese title

Title: 来自落入近极端克尔黑洞的引力波

Abstract: We study numerically in the time domain the linearized gravitational waves emitted from a plunge into a nearly extremal Kerr black hole by solving the inhomogeneous Teukolsky equation. We consider spinning black holes for which the specific spin angular momentum $a/M=1-\epsilon$, and we consider values of $\epsilon\geq 10^{-6}$. We find an effective transient behavior for the quasi-normal ringdown: the early phase of the quasi-normal ringdown is governed by a decay according to inverse time, with frequency equaling twice the black hole's horizon frequency. The smaller $\epsilon$ the later the transition from this transient inverse time decay to exponential decay. Such sources, if exist, may be interesting potential sources for terrestrial or space borne gravitational wave observatories. Show Chinese abstract

Abstract: 我们在时域中数值研究了从落入近极端克尔黑洞的下落过程中发出的线性化引力波，通过求解非齐次泰科利方程。 我们考虑自旋角动量比为$a/M=1-\epsilon$的旋转黑洞，并考虑$\epsilon\geq 10^{-6}$的值。 我们发现准正则环鸣的瞬态行为：准正则环鸣的早期阶段由按反时间衰减的频率决定，该频率等于黑洞视界频率的两倍。 $\epsilon$越小，从这种瞬态反时间衰减过渡到指数衰减就越晚。 如果存在这样的源，它们可能成为地面或空间引力波观测站的有趣潜在源。