  The large galactic scales are connected to the many orders of magnitude
smaller supermassive black hole (SMBH) scales by an episodic cycle of feeding
and feedback. Active galactic nuclei (AGN) are powered by accretion onto SMBH
and the majority of AGN energy, in near-Eddington regime, is produced in thin
sub-pc accretion discs. Currently, it is very difficult to model processes that
occur on vastly different scales, ranging from the circumnuclear gas reservoirs
at tens to hundreds of parsecs, down to the accretion disc scales at <0.01 pc.
While sub-grid prescriptions used in large-scale or cosmological simulations
are able to reproduce large-scale feedback, we propose using a more realistic
model in parsec-scale simulations, where it is important to get accurate
timescales to understand how feedback affects gas dynamics and star formation
in the vicinity of the AGN. To test our approach we use a sub-resolution thin
accretion disc model, coupled to the SMBH, in a set of hydrodynamical
simulations of a retrograde collision between a gas ring and a molecular cloud
in an environment similar to the Galactic centre using the SPH code Gadget-3.
The disc-mediated feeding of the SMBH is relatively smooth and delayed compared
to an instantaneous feeding prescription. While the reduction of accretion due
to feedback is present in both accretion disc and instantaneous feeding
simulations, a clear central cavity appears only in accretion disc runs -
hinting that a less volatile accretion phase could have a greater impact on the
surrounding gas.
