Physics of Coevolution of Galaxies and Supermassive Black Holes
  A new model for coevolution of galaxies and supermassive black holes (SMBH)
is presented that is physically based. The evolutionary track starts with an
event that triggers a significant starburst in the central region of a galaxy.
In this model, the main SMBH growth takes place in post-starburst phase fueled
by recycled gas from inner bulge stars in a self-regulated fashion on a time
scale that is substantially longer than 100Myrs and at a diminishing Eddington
ratio with time. We argue that the SMBH cannot gorge itself during the
starburst phase, despite the abundant supply of cold gas, because star
formation is a preferred mode of gas consumption in such an environment than
accretion to the central SMBH. We also show that feedback from star formation
is at least as strong as that from AGN and thus, if star formation is in need
of being quenched, AGN feedback generally does not play the primary role. The
predicted relation between SMBH mass and bulge mass/velocity dispersion is
consistent with observations. A clear prediction is that early-type galaxy
hosts of high Eddingtion rate AGNs are expected to be light-blue to green in
optical color, gradually evolving to the red sequences with decreasing AGN
luminosity. A suite of falsifiable predictions and implications with respect to
relationships between various types of galaxies and AGN, and others, are made.
For those where comparisons to extant observations are possible, the model
appears to be in good standing.
