There is evidence that every galaxy contains at least a central super massive black hole (mass range 10^6-10^8 solar masses).The mass of the black hole is estimated to be about 1/1000 the mass of its host galaxy. Further, the best studied cases show a correlation between the mass of the black hole and the amplitude of the potential depth of the galaxy.
I will explore physical mechanisms for this intriguing correlation and its implication on the effect of black holes on shaping the properties of galaxies.