2006/01/19 by Andrea Cattaneo, Cattaneo, Andrea
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0601456
4 pages, 2 figures, submitted as a Letter to MNRAS
arxiv created 2006/01/19 · openalex publication_date 2006/01/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
I consider a toy model of self-regulated black hole accretion. The black hole grows through Bondi accretion and a fraction of the accretion power is distributed as thermal feedback into the surrounding gas. The gas expands or contracts until AGN heating and radiative cooling balance each other. The balance of heating and cooling is used to determine a quasi-equilibrium temperature at which the black hole accretes in self-regulated equilibrium with the surrounding intergalactic medium. This temperature grows with the black hole mass. The temperature increase is very steep around a critical black hole mass due to the shape of the cooling function. The quasi-equilibrium temperature cannot exceed the virial temperature or the AGN will drive a thermal wind. This limits the black hole mass to a maximum value determined by the depth of the potential well. In the regime in which cooling is dominated by bremsstrahlung, this model determines a relation between black hole mass and halo characteristic velocity of the form MBH ~ v4. The predictions of the model are consistent with the observed black hole mass -- bulge velocity dispersion relation.