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We study the relation between obscuration and supermassive black hole (SMBH)growth using a large sample of hard X-ray selected Active Galactic Nuclei(AGN). We find a strong decrease in the fraction of obscured sources above theEddington limit for dusty gas ($\log \lambda_{\rm Edd}\gtrsim -2$) confirmingearlier results, and consistent with the radiation-regulated unification model.This also explains the difference in the Eddington ratio distribution functions(ERDFs) of type 1 and type 2 AGN obtained by a recent study. The break in theERDF of nearby AGN is at $\log \lambda_{\rm Edd}^{*}=-1.34\pm0.07$. Thiscorresponds to the $\lambda_{\rm Edd}$ where AGN transition from having most oftheir sky covered by obscuring material to being mostly devoid of absorbingmaterial. A similar trend is observed for the luminosity function, whichimplies that most of the SMBH growth in the local Universe happens when the AGNis covered by a large reservoir of gas and dust. These results could beexplained with a radiation-regulated growth model, in which AGN move in the$N_{\rm H}-\lambda_{\rm Edd}$ plane during their life cycle. The growth episodestarts with the AGN mostly unobscured and accreting at low $\lambda_{\rm Edd}$.As the SMBH is further fueled, $\lambda_{\rm Edd}$, $N_{\rm H}$ and coveringfactor increase, leading AGN to be preferentially observed as obscured. Once$\lambda_{\rm Edd}$ reaches the Eddington limit for dusty gas, the coveringfactor and $N_{\rm H}$ rapidly decrease, leading the AGN to be typicallyobserved as unobscured. As the remaining fuel is depleted, the SMBH goes backinto a quiescent phase.

BASS XXXVII: The role of radiative feedback in the growth and obscuration properties of nearby supermassive black holes