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Paper: Does Close Interaction between Galaxies Induce Nuclear Activity?
Volume: 421, Galaxies in Isolation: Exploring Nature Versus Nurture
Page: 115
Authors: Dultzin, D.; Krongold, Y.; González, J. J.; Hernández-Toledo, H.
Abstract: We review the biases which have led to contradictory results on the effects of interactions in triggering nuclear activity in galaxies. We can now neatly show that Sy2s are in close ( < 100kpc ) physical interaction with the same frequency as most starburst (SB) galaxies, and this frequency is significantly higher than the one for Sy1s which in turn, is similar to the one for “normal” (non-active) galaxies. Next, we present results from a complementary approach: the analysis of the incidence of activity in close pairs. For this we carried out observations for a well defined sample of interacting galaxies: The isolated mixed morphology ( E + S ) pairs. One result indicates that AGN activity tends to appear in pairs of galaxies which are physically closer to one another. A striking result is that only one, out of 39 clear-cut AGN in our sample, is of type 1. This frequency of type 1 activity is too low to be explained with an obscuration/orientation effect alone. We discuss an alternative -though inclusive- model to the so called “Unified Model”.
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