Håkan Andréasson: On the rotation curves for axially symmetric disk solutions of the Vlasov-Poisson system

A large class of flat axially symmetric solutions to the Vlasov-Poisson
system is constructed with the property that the corresponding rotation curves are
approximately flat, slightly decreasing or slightly increasing. The rotation
curves are compared with measurements from real galaxies and satisfactory
agreement is obtained. These facts raise the question whether the
observed rotation curves for disk galaxies may be explained without introducing dark matter.
Furthermore, it is shown that for the ansatz we consider stars on
circular orbits do not exist in the neighborhood of the boundary of the steady state.