Surface density of the simulation with Σ₀ = 10 M_⊙ pc⁻² and b_cool = 1 at different spatial scales. Top (253 Myr): in the center an irregular ring can be seen. The overall structure is very chaotic and some high-mass fragments are perceivable. Bottom (744 Myr): in the central region a marginally stable self-gravitating disk has formed, embedded in a gas-poor environment. Thus, the central accretion disk couples only weakly to the kiloparsec-scale gas disk. Angular momentum transfer to the outer parts of the galaxy is suppressed and consequently the accretion rate onto the black hole declines.