Are starbursts the result of the fine tuning of dynamical timescales?

Abstract

When disk galaxies interact or collide gravitational fluctuations often generate density waves. We present cloud-fluid models of a particularly simple form of colliding galaxy, ring galaxies. Our models suggest that a certain degree of fine tuning between relevant timescales is required to obtain strong starbursts in the wave. Although the models are specific to ring galaxies, the results are applicable to other kinds of tidal interaction and to the early stages of certain types of galaxy merger. The results may explain why not all disturbed galaxies exhibit strong starburst activity.