Abstract
We probe the cause of the elevated star formation in host galaxies of Seyfert 2 nuclei compared with Seyfert 1 hosts and with field galaxies. 12CO (1-0) observations of a large sample of Seyfert galaxies indicate no significant difference in the total amount of molecular gas as a function of the Seyfert nuclear type, nor are Seyfert galaxies significantly different in this regard from a sample of field galaxies once selection effects are accounted for. Therefore, the total amount of molecular gas is not responsible for the enhanced star-forming activity in Seyfert 2 hosts. To probe how this gas is being converted more efficiently into stars in Seyfert 2 hosts than in the other galaxies, we investigate the occurrence of bars, interactions, and distorted morphologies among Seyfert galaxies. We find a significantly higher rate of asymmetric morphologies for Seyfert 2 galaxies with respect to Seyfert 1 galaxies and field galaxies. Relative to field galaxies, the effect is at a greater than 99.9% confidence level. The presence of asymmetric morphologies in individual Seyfert galaxies is correlated with their tendency to exhibit enhanced star-forming activity. These results suggest that asymmetric morphologies are an important cause for the link between Seyfert type and star-forming activity: bars and distortions in Seyfert 2 hosts are likely both to enhance star-forming activity and to funnel gas into the nuclear region, thus obscuring and possibly contributing to the feeding of the active nucleus.
Original language | English (US) |
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Pages (from-to) | 552-569 |
Number of pages | 18 |
Journal | Astrophysical Journal |
Volume | 485 |
Issue number | 2 PART I |
DOIs | |
State | Published - 1997 |
Keywords
- Galaxies: active
- Galaxies: ISM
- Galaxies: Seyfert
- Galaxies: structure
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science