Neutral gas outflows and inflows in infrared-faint seyfert galaxies

Abstract

Previous studies of the Na I D interstellar absorption line doublet have shown that galactic winds occur in most galaxies with high infrared luminosities. However, in infrared-bright composite systems where a starburst coexists with an active galactic nucleus (AGN), it is unclear whether the starburst, the AGN, or both are driving the outflows. The present paper describes the results from a search for outflows in 35 infrared-faint Seyferts with 109.9 < 10 11, or, equivalently, star formation rates (SFRs) of 0.4-9 M ⊙ yr-1, to attempt to isolate the source of the outflow. We find that the outflow detection rates for the infrared-faint Seyfert1s (6%) and Seyfert2s (18%) are lower than previously reported for infrared-luminous Seyfert1s (50%) and Seyfert2s (45%). The outflow kinematics of infrared-faint and infrared-bright Seyfert2 galaxies resemble those of starburst galaxies, while the outflow velocities in Seyfert1 galaxies are significantly larger. Taken together, these results suggest that the AGN does not play a significant role in driving the outflows in most infrared-faint and infrared-bright systems, except the high-velocity outflows seen in Seyfert1 galaxies. Another striking result of this study is the high rate of detection of inflows in infrared-faint galaxies (39% of Seyfert1s, 35% of Seyfert2s), significantly larger than in infrared-luminous Seyferts (15%). This inflow may be contributing to the feeding of the AGN in these galaxies, and potentially provides more than enough material to power the observed nuclear activity over typical AGN lifetimes. © 2010. The American Astronomical Society.