SIMULATIONS OF STELLAR DISKS IN GALAXIES WITH NON-NEWTONIAN INTERACTIONS

We describe gravitational N-body simulations to investigate whether va rious non-Newtonian interactions between the stars of a system could e xplain the flat rotational curves which are characteristic of actual i solated spiral galaxies. It is shown that replacing the standard Newto nian interaction by the models of Sanders (1984), Kuhn and Kruglyak (1 987) and Milgrom (1983), no massive halo (or dark matter) is required to produce the flat rotational curves of the systems under considerati on. All models also generate the exponential surface mass density dist ribution which is in agreement with that observed in disk-shaped galax ies. In relation to the spiral structure of galaxies, we present the e vidence that the non-Newtonian interactions can reproduce the multiple armed patterns in stellar disks without dark matter.