标题： 引力电磁近似下的引力磁偶极及其速度旋转曲线 显示英文标题

标题： The Gravito-Electromagnetic Approximation to the Gravimagnetic Dipole and its Velocity Rotation Curve

摘要： 鉴于观测到的螺旋星系的平坦旋转曲线，并考虑到在牛顿引力中，一个有限范围内的静态轴对称质量分布或暗物质涡旋，在距离与该涡旋垂直于星系盘的范围相当时，其速度旋转曲线会呈现出一定程度的平坦化这一简单事实，本文考虑了这样一种可能性：即这种旋转曲线的平坦化可能是某种纯粹由引力特性决定的静态轴对称时空曲率的表现，而不必引入暗物质粒子。这一可能性是在重力磁偶极子携带相反的纽特（NUT）电荷的情况下，并在Misner弦张力极限下作为爱因斯坦场方程的一个精确真空解来研究的。 为了比全面研究其测地线更易于评估这一建议的潜力，文中在弱场引力电磁学和非相对论动力学的范围内分析了这种情况。 从而确实得到了有趣且令人鼓舞的结果。 显示英文摘要

摘要： In view of the observed flat rotation curves of spiral galaxies and motivated by the simple fact that within newtonian gravity a stationary axisymmetric mass distribution or dark matter vortex of finite extent readily displays a somewhat flattened out velocity rotation curve up to distances comparable to the extent of such a vortex transverse to the galaxy's disk, the possibility that such a flattening out of rotation curves may rather be a manifestation of some stationary axisymmetric space-time curvature of purely gravitational character, without the need of some dark matter particles, is considered in the case of the gravimagnetic dipole carrying opposite NUT charges and in the tensionless limit of its Misner string, as an exact vacuum solution to Einstein's equations. Aiming for a first assessment of the potential of such a suggestion easier than a full fledged study of its geodesics, the situation is analysed within the limits of weak field gravito-electromagnetism and nonrelativistic dynamics. Thereby leading indeed to interesting and encouraging results.