Activity induced by Gravitational Interaction in Galaxy Pairs

A systematic study of the nuclear emission of a sample of 97 spirals in isolated galaxy pairs with mixed morphology (E+S) shows that: 1) AGN activity is found in 40% of the spiral galaxies in these pairs, 2) Only one out of the 39 AGN found has type 1 (Broad line Component) activity, and 3) AGN tend to have closer companions than star forming galaxies. These results are at odds with a simple Unified Model for Seyferts, where only obscuration/orientation effects are of relevance, and neatly support an evolutionary scenario where interactions trigger nuclear activity, and obscuration/orientation effects may be complementary in a certain evolutionary phase.
Comment: Proceedings of The Central Kiloparsec: Active Galactic Nuclei and Their Hosts, held in Crete, Greece, 4 - 6 June 2008, to appear in Volume 79 of the Memorie della Societa Astronomica Italiana