Relativistic Gravitation and Astrophysics

点击翻译按钮获取中文摘要

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.