Dark matter comprising a Bose-Einstein condensate (BEC) forms structures of the size of its coherence length, as determined by equilibrium between quantum pressure and gravitational attraction. This is also the core size of quantum vortices in a BEC superfluid. From the density and rotation curve of the Andromeda Galaxy (M31) we estimate the particle mass, particle density, coherence length, critical temperature, critical angular frequency, and vortex line density of the dark matter condensate composing the halo.
Class. Quantum Grav.