Black Hole Outflows
  I show that Eddington accretion episodes in AGN are likely to produce winds
with velocities $v \sim 0.1c$ and ionization parameters up to $\xi \sim 10^4$
(cgs), implying the presence of resonance lines of helium-- and hydrogenlike
iron. These properties are direct consequences of momentum and mass
conservation respectively, and agree with recent X-ray observations of fast
outflows from AGN. Because the wind is significantly subluminal, it can persist
long after the AGN is observed to have become sub--Eddington. The wind creates
a strong cooling shock as it interacts with the interstellar medium of the host
galaxy, and this cooling region may be observable in an inverse Compton
continuum and lower--excitation emission lines associated with lower
velocities. The shell of matter swept up by the (`momentum--driven') shocked
wind must propagate beyond the black hole's sphere of influence on a timescale
$\la 3\times 10^5$ yr. Outside this radius the shell stalls unless the black
hole mass has reached the value $M_{\sigma}$ implied by the $M - \sigma$
relation. If the wind shock did not cool, as suggested here, the resulting
(`energy--driven') outflow would imply a far smaller SMBH mass than actually
observed. In galaxies with large bulges the black hole may grow somewhat beyond
this value, suggesting that the observed $M -\sigma$ relation may curve upwards
at large $M$. Minor accretion events with small gas fractions can produce
galaxy--wide outflows with velocities significantly exceeding $\sigma$,
including fossil outflows in galaxies where there is little current AGN
activity. Some rare cases may reveal the energy--driven outflows which sweep
gas out of the galaxy and establish the black hole--bulge mass relation.
However these require the quasar to be at the Eddington luminosity.
