Feedback from Nuclear Star Clusters and SMBHs
  The observed super-massive black hole (SMBH) mass -- galaxy velocity
dispersion ($M_{\rm cmo} - \sigma$) correlation, and the similar correlation
for nuclear star clusters, may be established when winds/outflows from the CMO
("central massive object") drive gas out of the potential wells of classical
bulges. Timescales of growth for these objects may explain why smaller bulges
appear to host preferentially NCs while larger ones contain SMBHs only.
  Despite much recent progress, feedback processes in bulge/galaxy formation
are far from being understood. Our numerical simulations show that that
understanding how the CMO feeds is as important a piece of the puzzle as
understanding how its feedback affects its host galaxy.
