Binary Black Holes and Gravitational Radiation

*9800731 Winicour这个项目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。该方法使用了一种经过充分测试的广义相对论三维特征演化代码。该代码是由该组织作为二元黑洞大挑战联盟的一部分开发的。边界算法的策略是柯西特征匹配，它使用内部柯西算法和外部特征算法来执行全局进化，并通过世界管界面进行匹配。虽然这两种方法本身都不能覆盖整个感兴趣的物理区域，但它们相辅相成，因为它们适用于最合适的地方-源附近的柯西方法和辐射区的特征方法。广义相对论是爱因斯坦对牛顿引力理论的重新表述，它预测加速质量产生引力波，类似于电荷产生电磁波或池塘中运动的物体产生水波。对双星脉冲星轨道的观测已经推断出引力波的存在。正在建设中的LIGO天文台将具有足够的灵敏度，可以直接探测来自遥远星系的引力波。这个项目的目标是开发一种计算双星系统中两个黑洞相互作用和合并时所发出的波的性质的方法。这对LIGO的成功非常重要。双星黑洞是波的主要来源之一，LIGO就是为了探测这种波而设计的。这一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.***