ABSTRACT

Results of 3D numerical simulations of a two-component self-gravitating galactic disk embedded in a ‘live’ halo are presented. The pure stellar disk is chosen to be globally unstable and forms a stellar bar. A ‘seed’ black hole (BH) of 5 x 107 M⊙ with an ‘accretion’ radius of 20 pc is placed at the center. The details on the numerical method are given in Shlosman and Heller (these proceedings and references therein). Here we study the effects of star formation (SF) which is introduced when (1) the gas is Jeans unstable; and (2) the gas density exceeds ∼ 100 M⊙ pc-3. The formed massive stars account for the gas heating by means of line-driven winds and by supernovae, assuming an efficiency of kinetic-to-thermal energy conversion of a few percent. Models with and without SF are compared and only the robust features are emphasized.

We find that the SF has induced angular momentum loss by the gas and has increased the radial inflow by a factor < 3. We also find that (1) SF is concentrated at the apocenters of the gaseous circulation in the bar and in the nuclear region; (2) the nuclear starburst phase appears to be very luminous (quasar-like) and episodic; and (3) the nuclear starburst phase correlates with the catastrophic growth of the BH. Without the pre-existing BH, the gas at the center (few x 100 pc) becomes dynamically unstable and forms a gaseous bar which drives a further inflow. The gaseous bar may fission into a massive cloud binary system.