The Fueling of Nuclear Activity: The Bar Properties of Seyfert and Normal Galaxies

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Abstract
We use a recent near-infrared imaging survey of samples of Seyfert and normal galaxies to study the role of bars in the fueling of nuclear activity. The active galaxy sample includes Seyfert galaxies in the Revised Shapely-Ames (RSA) catalog and Sandage & Tammann's extension of this catalog. The normal galaxies were selected to match the Seyfert sample in Hubble type, redshift, inclination, and blue luminosity. All the galaxies in both samples classified as barred in the RSA catalog are also barred in the near-infrared. In addition, ~55% of the galaxies classified as nonbarred in the RSA show evidence for bars at 2.1 μm. Overall, ~70% of the galaxies observed show evidence for bar structures. The incidence of bars in the Seyfert and normal galaxies is similar, suggesting that Seyfert nuclei do not occur preferentially in barred systems. Furthermore, a slightly higher percentage of normal galaxies have multiple-bar structures. A significant percentage of the Seyfert galaxies in our sample show no evidence for the presence of a bar even in the near-infrared. This suggests either that large-scale kiloparsec bars are not a universal fueling mechanism in Seyfert galaxies or that the bars in the nonbarred Seyferts were recently destroyed, possibly by the formation of the central black hole.
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