Suppressing hot gas accretion to supermassive black holes by stellar
  winds
  We argue that one of the basic assumptions of the Bondi accretion process,
that the accreting object has zero pressure, might not hold in many galaxies
because of the pressure exerted by stellar winds of star orbiting the central
super massive black hole (SMBH). Hence, the Bondi accretion cannot be used in
these cases, such as in the galaxy NGC 3115. The winds of these high-velocity
stars are shocked to temperatures above the virial temperature of the galaxy,
leading to the formation of a hot bubble of size ~0.1-10 pc near the center.
This hot bubble can substantially reduce the mass accretion rate by the SMBH.
If the density of the hot bubble is lower than that of the interstellar medium
(ISM), a density-inversion layer is formed. As the gas loses energy by X-ray
radiation, eventually more mass of the cooling shocked stellar winds will be
accreted to the SMBH. This accretion will be of cold clumps. After a period of
millions of years of low AGN activity, therefore, a stronger AGN activity will
occur that will heat and expel gas, much as in cooling flow clusters. Adding to
other problems of the Bondi process, our results render the Bondi accretion
irrelevant for AGN feedback in cooling flow in galaxies and small groups of
galaxies and during galaxy formation.
