  The observational link between Supermassive Black Holes (SMBH) and galaxies
at low redshift seems to be very tight, and statistically the global evolution
of star formation activity and BH accretion activity also seem to trace each
other closely. However, pinning down the co-evolution of galaxies and BH on an
object-by-object basis remains elusive. I present results from new models for
the joint evolution of galaxies, SMBH, and AGN, which may be able to help
resolve some of the observational puzzles. A unique aspect of these models is
our treatment of self-regulated BH growth based on hydrodynamic simulations of
galaxy-galaxy mergers. Although these models do quite well at reproducing the
observed evolution of galaxies, they do not reproduce the observed history of
BH accretion, predicting too much early accretion and not enough at late times.
I suggest two possible resolutions to this problem.
