GALACTIC DYNAMICS VIA GENERAL RELATIVITY: A COMPILATION AND NEW DEVELOPMENTS

Abstract

We consider the consequences of applying general relativity to the description of the dynamics of a galaxy, given the observed flattened rotation curves. The galaxy is modeled as a stationary axially symmetric pressure-free fluid. In spite of the weak gravitational field and the nonrelativistic source velocities, the mathematical system is still seen to be nonlinear. It is shown that the rotation curves for various galaxies as examples are consistent with the mass density distributions of the visible matter within essentially flattened disks. This obviates the need for a massive halo of exotic dark matter. We determine that the mass density for the luminous threshold as tracked in the radial direction is 10-21.75 kg · m -3 for these galaxies and conjecture that this will be the case for other galaxies yet to be analyzed. We present a velocity dispersion test to determine the extent, if of any significance, of matter that may lie beyond the visible/HI region. This is determined by examining the rotation curves at different galactic latitudes, bringing into consideration the global dynamical structure of the galaxy. The demand for global consistency applies not only to our own but also to all proposed models and theories. Various comments and criticisms from colleagues are addressed.