Black hole wind speeds and the M-sigma relation
Abstract
We derive an Mbh-sigma relation between supermassive black hole mass and stellar velocity dispersion in galaxy bulges, that results from self-regulated, energy-conserving feedback. The relation is of the form Mbh vw sigma5, where vw is the velocity of the wind driven by the black hole. We take a sample of quiescent early-type galaxies and bulges with measured black hole masses and velocity dispersions and use our model to infer the wind speeds they would have had during an active phase. This approach, in effect, translates the scatter in the observed Mbh-sigma relation into a distribution of vw. There are some remarkable similarities between the distribution of black hole wind speeds that we obtain and the distributions of outflow speeds observed in local AGN, including a comparable median of vw = 0.035 c.