ITR: Numerical and Computational Tools for Binary Black Hole Simulations

其目标是提供新的数值和计算工具，以达到一个新的里程碑：对最后几个螺旋形轨道的两个黑洞及其猛烈的碰撞和合并进行计算机模拟。这样一个二元黑洞系统的动力学受爱因斯坦广义相对论方程的支配。为了在计算机上求解非常复杂的爱因斯坦方程，开发了特殊的方法来提高计算效率，以便在常规基础上进行完全三维模拟。这需要考虑到爱因斯坦广义相对论的特点，特别是找到良好的显式坐标(以便计算机能够处理广义相对论的“一切都是相对的”)，并处理隐藏在黑洞中的时空奇点。值得注意的是，直到今天，广义相对论的两体问题仍然没有得到解决。尤其是双星中两个黑洞的动力学问题已经引起了相当大的关注，但甚至连两个黑洞的单一轨道都没有被模拟过。黑洞的轨道运动遵循螺旋运动，导致黑洞的碰撞和合并，预计这将产生大量的引力辐射。引力波天文学家群体迫切地等待着计算机模拟对黑洞合并波的预测。

The goal is to provide new numerical and computational tools to reach a new milestone: performing computer simulations of the last fewinspiraling orbits of two black holes and their violent collision and merger. The dynamics of such a binary black hole system is governed by Einstein's equations for general relativity. To solve the very complex Einstein equations on the computer, special methods are developed that improve the computational efficiency so that fully three-dimensional simulations become possible on a routine basis. This requires taking the pecularities of Einstein's general relativity into account, in particular finding good explicit coordinates (so that the computer can handle the `everything is relative' of general relativity) and dealing with the spacetime singularities that lurk inside black holes.It is remarkable that even today the two body problem of general relativity still remains unsolved. Especially the problem of dynamics of two black holes in a binary has drawn considerable attention, butnot even a single orbit of two black holes has been simulated. The orbital motion of black holes follows a spiral that leads to thecollision and merger of the black holes, which is expected to produce large amounts of gravitational radiation. The community of gravitational wave astronomers urgently awaits predictions for the merger waves of black holes from computer simulations.