Black hole mergers and unstable circular orbits
Black hole mergers and unstable circular orbits
复制标题
黑洞合并和不稳定的圆形轨道
DOI：
10.1088/0264-9381/24/12/s07
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发表时间：
2007
影响因子：
3.5
通讯作者：
Deepak Khurana
中科院分区：
文献类型：
--
作者：
F. Pretorius;Deepak Khurana
本文描述了广义相对论中一类等质量、非自旋、偏心双黑洞系统合并的数值模拟。我们表明，适当的微调的初始条件，可以达到一个区域的参数空间，我们表示的阈值立即合并。在这里，双星进入一个近圆形轨道的密切相互作用阶段，在那里停留一段与参数空间中阈值的对数距离成比例的时间，然后分离或合并形成一个单一的克尔黑洞。为了更好地理解这一现象，我们研究了中心Kerr黑洞赤道测地线演化中的一个类似问题。对于适当类别的初始条件，存在类似的捕获阈值，并且调整阈值测地线接近克尔时空的不稳定圆形测地线之一。值得注意的是，一个自然映射的参数的测地线的等质量系统，标度指数描述的漩涡阶段的每个系统是非常相似的。武装这个孤独的一块的证据表明，一个近似的对应关系可能存在于近阈值的测地线和通用的二进制合并的演变，我们说明了如何使用这些信息来估计的横截面和能量发射的超相对论性黑洞散射问题。这可能最终用于在额外维度的情况下，黑洞产生的大型强子对撞机的部分子碰撞的相关问题提供估计。
We describe recent numerical simulations of the merger of a class of equal mass, non-spinning, eccentric binary black hole systems in general relativity. We show that with appropriate fine tuning of the initial conditions one can reach a region of parameter space we denote the threshold of immediate merger. Here, the binary enters a phase of close interaction in a near-circular orbit, stays there for an amount of time proportional to the logarithmic distance from the threshold in parameter space, then either separates or merges to form a single Kerr black hole. To gain a better understanding of this phenomenon, we study an analogous problem in the evolution of equatorial geodesics about a central Kerr black hole. A similar threshold of capture exists for appropriate classes of initial conditions, and tuning to threshold the geodesics approach one of the unstable circular geodesics of the Kerr spacetime. Remarkably, with a natural mapping of the parameters of the geodesic to that of the equal mass system, the scaling exponents describing the whirl phase of each system turn out to be quite similar. Armed with this lone piece of evidence that an approximate correspondence might exist between near-threshold evolution of geodesics and generic binary mergers, we illustrate how this information can be used to estimate the cross section and energy emitted in the ultra-relativistic black hole scattering problem. This could eventually be of use in providing estimates for the related problem of parton collisions at the large hadron collider in extra dimension scenarios where black holes are produced.