Dark matter isn't real. It's obviously gravitational torsion accelerating matter farther out.
>b-but objects at the edge are moving just to fast to be gravitationally bound to the galaxy and should go flying off.
Wrong. Gravitational waves are waves which roll turbulently. As matter converges, its energy is transferred to the field in a similar fashion to convection currents in an atmosphere. Consider a boat passing over waves. The masses encountering these rolling waves cannot generally release more field so that they can roll with the wave and as such are accelerated radially inward towards the center of the galaxy. Matter and the field are one in the same thing, matter is merely a manifold of the field. You can imagine a black hole as the unwinding of the manifold in order to prevent the field itself from tearing. This is what gravity is. As the gravitation field resonates through the galactic plane, energy is transferred to objects within it, corresponding to an increase in brightness. Inertia by matter fragments as field.