Abstract
I present new results in our study of the starburst-AGN connection in the central kpc of 230 infrared galaxies. We developed theoretical optical grids for determining the relative contribution of AGN vs. starburst emission in composite galaxies. The grids are based on stellar population synthesis, photoionization and shock models. We compared the contribution from an AGN with indicators of merger evolution for our sample. Our results support an evolutionary scenario in which starburst activity is initially triggered by tidal interactions. As gas is funnelled towards the merger nucleus, an AGN is activated. Towards later stages of the merger, circumnuclear starburst activity becomes the dominant excitation mechanism.
