Self-gravity stabilises topological vortices in ultralight scalar field dark matter

We investigate the formation and long-term evolution of topological vortices in a self-gravitating ultralight scalar field dark matter model. Using 2D numerical simulations, we show that self-gravity stabilises vortices above a critical effective coupling, leading to a quasi-stationary vortex population. The transition is accompanied by a constant gravitational-to-kinetic energy ratio of about 0.25. The model predicts characteristic scales in the matter power spectrum and a possible correlation between vortex distribution and galaxy positions, testable with future surveys.