Galaxy Formation, Bars and QSOs

Abstract

A model that accounts for the brief flaring of QSOs in the early stages of galaxy formation is proposed. I argue that a bar must develop early in the life of nearly every galaxy and that gas to create and fuel the QSO is driven into the center of the galaxy by the bar. The QSO lifetime, and the mass of its central engine, are also controlled by large-scale dynamics, since the fuel supply is shut off after a short period by the development of an inner Lindblad resonance. This resonance causes the gas inflow along the bar to stall at a distance of a few hundred parsecs from the center. The ILR develops as a result of previous inflow, making quasar activity self-limiting. The bars are weakened and can be destroyed by the central mass concentration formed in this way.