Quenching black hole accretion by active galactic nuclei feedback

TL;DR

This study uses simulations to show that wind feedback from active galactic nuclei can significantly reduce black hole accretion rates, explaining the dimness of many local galactic nuclei.

Contribution

It demonstrates that wind feedback, rather than radiation, effectively decreases black hole accretion rates in low-luminosity AGNs, aligning models with observations.

Findings

Wind feedback reduces accretion rates by a factor of 33-400.

Radiation feedback has minimal impact on accretion rates.

Results help explain the dimness of many local galactic nuclei.

Abstract

Observations of many dim galactic nuclei in local universe give good estimation of gas density and temperature at Bondi radius. If we assume the black hole accretes at Bondi accretion rate and radiates at efficiency of low-luminosity hot accretion flow, the predicted nuclei luminosity can be significantly higher than observations. Therefore, the real black hole mass accretion rate in these sources may be significantly smaller than the Bondi value. Active galactic nuclei (AGN) feedback may be responsible for decreasing black hole accretion rate to values much smaller than Bondi rate. We perform two-dimensional simulations of low angular momentum accretion flow at parsec and sub-parsec 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, effects of radiation feedback in decreasing black hole accretion rate are small. However, wind feedback can effectively decrease the black hole mass accretion rate. Due to the decrease of accretion rate, the black hole luminosity can be decreased by a factor of $\sim 33-400$. The results may be useful to explain why many galactic nuclei in the local universe are so dim.