Friday, June 4, 2010, Noon, Phillips Auditorium
No Merger-AGN Connection Since z~1
Mauricio Cisternas (MPIA, Heidelberg)
| What is the relevance of major mergers and interactions as triggering mechanisms for AGN activity? We tackle this longstanding question by studying a sample of 140 AGN host galaxies over z ~ 0.3-1.0 with high-resolution HST/ACS imaging from the COSMOS field. We perform a visual analysis of their morphologies, looking for signatures of interactions and/or mergers that could potentially be related to the AGN fueling/triggering. To establish the significance of any distortions present in our AGN hosts, we compare them with a matched control sample of inactive galaxies from the same dataset. After carrying out this analysis with 10 independent human classifiers, we find no significant enhancement distortion rate for the AGN hosts over the inactive galaxies. Our findings provide direct evidence that, since z~1, major merging is not the primary mechanism for triggering AGN activity. |
