Average density distribution in an FDM simulation performed with GAMER. The yellow region marks a soliton core that forms spontaneously at the center of an FDM halo. An animation of this figure is available. It has a total duration of 113 s and illustrates the evolution from the initial condition to the onset of soliton condensation. Initially, the halo remains near equilibrium, exhibiting only granular density fluctuations. After ∼100 Gyr, a soliton core with radius ∼3 kpc forms and gradually grows more compact and massive.

(An animation of this figure is available in the online article.)

(An animation of this figure is available.)

The video/animation of this figure is available in the online journal.