Compact nuclear objects and properties of their parent galaxies

We consider the relationship between the masses of the compact nuclear objects in the centers of disky galaxies - supermassive black holes (SMBHs) or nuclear star clusters (NCs) - and such parameters as the maximal velocity of rotation V _max, obtained from the rotation curves, indicative dynamical mass M ₂₅, and the color index (B-V) of their parent galaxies. It was found that the mass of nuclear clusters M _nc correlates more closely with the velocity of rotation and total mass of galaxies than the mass of supermassive black holes M _bh. The dependence of masses of the central objects on the color index is bimodal: galaxies of the red group (red-sequence), which have (B-V) > 0.6-0.7, differ from bluer galaxies, by higher values of M _bh for similar host-galaxy parameters. In contrast, in the diagrams for nuclear clusters the ``blue'' and ``red'' galaxies form unified sequences. It agrees with scenarios in which most red-group galaxies form as a result of loss of interstellar gas in a stage of high nuclear activity in galaxies whose central black-hole masses are high, exceeding 10⁶ - 10⁷ M _⊙ (depending on the total mass of the galaxy). The active growth of nuclear star clusters possibly begun after the violent AGN activity.