Relativistic Gravitation and Astrophysics

该研究计划将继续将后牛顿引力辐射的计算扩展到最高的可行阶数，目标是为引力辐射观测站开发更准确和可靠的理论模板，以及更深入地理解爱因斯坦方程应用于高度动态，强引力情况。 这项工作将涉及（i）在这种近似方法的基础上进行正式的理论工作，（ii）在引力辐射和运动方程中对高阶效应进行具体计算，以及（iii）在后牛顿方法和数值相对论方法之间建立一个接口，这必须用于分析两个天体的后期螺旋和合并。 中子星或黑洞的螺旋双星系统是有希望的引力辐射源，可以通过更大规模的激光干涉引力观测站探测到，例如美国的LIGO和意大利-法国的VIRGO项目，计划在本世纪末完成。 对这种辐射的探测和研究将开辟引力波天文学的新领域，并为广义相对论提供重要的新检验。 为了最大限度地利用这些探测器的输出，至关重要的是手头上有非常精确的引力波形“模板”：从广义相对论中对源参数范围内的波的形状和频率演变进行详细的理论预测。 这些模板将被用作“过滤器”，从探测器的噪声输出中提取有用的信息，例如是否检测到引力波，以及源的内在特征，例如其方向和距离，以及其组件的质量和自旋。 对于所有，但最后，强烈的广义相对论合并的两个机构，理论方法的基础上连续的“后牛顿”近似一般relativity已被证明是非常有价值的发展这些模板。

This research program will continue to extend post-Newtonian calculations of gravitational radiation to the highest practicable order, with the goal of developing more accurate and reliable theoretical templates for gravitational radiation observatories, as well as of achieving deeper understanding of Einstein's equations as applied to highly dynamical, strong-gravity situations. This effort will involve (i) formal theoretical work on the foundations of such approximation methods, (ii) specific calculation of higher-order effects in both the gravitational radiation and the equations of motion, and (iii) development of an interface between the post-Newtonian methods and those of numerical relativity, which must be used to analyze the late inspiral and merger of the two bodies. Inspiralling binary systems of neutron stars or black holes are promising sources of gravitational radiation detectable by kilometer-scale, laser-interferometric gravitational observatories, such as the US LIGO and Italian-French VIRGO projects, scheduled to be completed by the end of this decade. Detection and study of this radiation will open a new field of gravitational-wave astronomy, and provide important new tests of general relativity. In order to make maximum use of the output of these detectors, it is crucial to have on hand extremely accurate gravitational-waveform "templates": detailed theoretical predictions from general relativity of the shape and frequency evolution of the waves for ranges of source parameters. These templates will be used as "filters" to extract from the noisy output of the detectors useful information such as whether or not gravitational waves are detected, and the intrinsic characteristics of the source, such as its direction and distance, and the masses and spins of its components. For all but the final, strongly general relativistic coalescence of the two bodies, theoretical methods based on successive "post-Newtonian" approximations to general re lativity have proved to be extremely valuable in developing these templates.