Binary Black Holes and Gravitational Radiation

本课题的目标是为黑洞的柯西演化提供稳定、准确的边界条件，同时确定辐射波形。该方法使用了一个经过全面测试的广义相对论三维特征演化代码。这个代码是由这个小组开发的，作为二进制黑洞大挑战联盟的一部分。边界算法的策略是柯西特征匹配，使用内部柯西算法和外部特征算法进行全局进化，在世界管接口上匹配。虽然单独使用这两种方法都不能覆盖整个感兴趣的物理区域，但它们相互补充，因为它们应用在最合适的地方- - -源附近的柯西方法和辐射区内的特征方法。广义相对论是爱因斯坦对牛顿引力理论的重新表述，它预测加速的质量会产生引力波，类似于电荷产生电磁波或池塘中移动的物体产生水波的方式。引力波的存在已经从对双星脉冲星轨道的观测中推断出来。目前正在建设中的LIGO观测站将足够灵敏，可以直接探测到来自遥远星系的引力波。这个项目的目标是开发一种方法来计算双星系统中两个黑洞吸入和合并时所发射的波的性质。这对LIGO的成功至关重要。双黑洞是引力波的主要来源之一，也是LIGO设计用来探测引力波的。计算是基于广义相对论的一种新的计算方法

***9800731WinicourThe goal of this project is to provide stable, accurate boundary conditions for the Cauchy evolution of black holes, while at the same time determining the radiation waveform. The approach uses a fully tested 3-dimensional characteristic-evolution code for general relativity. The code was developed by this group as part of the Binary Black Hole Grand Challenge Alliance. The strategy for the boundary algorithm is Cauchy-characteristic matching, which carries out a global evolution using an interior Cauchy algorithm and an exterior characteristic algorithm, matched across a world-tube interface. While neither of the two methods alone would cover the entire physical region of interest, they complement each other because they are applied where they are most appropriate - the Cauchy method near the sources and the characteristic method in the radiation zone.General relativity, Einstein's reformulation of Newton's gravitational theory, predicts that accelerated masses produce gravitational waves analogous to the way charges produce electromagnetic waves or objects moving in a pond produce water waves. The existence of gravitational waves has already been inferred from observations of the orbits of binary pulsars. The LIGO observatories now under construction will be sensitive enough to detect directly gravitational waves from distant galaxies. The goal of this project is to develop a method for calculating the properties of waves emitted when two black holes in a binary system inspiral and coalesce. This is important for the success of LIGO. Binary black holes are one of the prime sources of the waves, which LIGO is designed to detect. The calculation is based upon a new computational approach to general relativity.***