Activity induced by Gravitational Interaction in Galaxy Pairs

TL;DR

This study investigates how gravitational interactions in galaxy pairs influence nuclear activity, revealing that interactions can trigger AGN activity and that AGN are more likely to have closer companions, challenging simple unified models.

Contribution

It provides evidence that galaxy interactions can induce nuclear activity and suggests an evolutionary scenario beyond simple orientation-based models.

Findings

40% of spiral galaxies in pairs host AGN

Most AGN are of type 2, with only one type 1

AGN tend to have closer companions than star-forming galaxies

Abstract

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.