Quenching Black Hole Accretion by Active Galactic Nuclei Feedback

Abstract

Observations of many dim galactic nuclei in the local universe give good estimations of gas density and temperature at the Bondi radius. If we assume the black hole accretes at the Bondi accretion rate and radiates at the efficiency of a low-luminosity hot accretion flow, the predicted nuclei luminosity can be significantly higher than that seen in observations. Therefore, the real black hole mass accretion rate in these sources may be significantly smaller than the Bondi value. Active galactic nucleus feedback may be responsible for decreasing the black hole accretion rate to values much smaller than the Bondi rate. We perform two-dimensional simulations of low-angular-momentum accretion flow at parsec and subparsec scales around low-luminosity active galactic nuclei (LLAGNs). We take into account the radiation and wind feedbacks of the LLAGN. The cross section of particle–particle interaction can be several orders of magnitude larger than that of photon–particle interaction. Therefore, we find that for the LLAGNs, the effects of radiation feedback in decreasing black hole accretion rates are small. However, wind feedback can effectively decrease the black hole mass accretion rate. Due to the decrease of the accretion rate, the black hole luminosity can be decreased by a factor of ∼33–400. These results may be useful for explaining why many galactic nuclei in the local universe are so dim.