Neutral Gas Outflows and Inflows in Infrared-Faint Seyfert Galaxies

TL;DR

This study investigates gas outflows and inflows in infrared-faint Seyfert galaxies, revealing low outflow detection rates and high inflow detection rates, suggesting limited AGN influence on outflows and potential feeding of the AGN through inflows.

Contribution

It provides new insights into the gas dynamics of infrared-faint Seyfert galaxies, highlighting the roles of star formation and AGN activity in driving outflows and inflows.

Findings

Low outflow detection rates in infrared-faint Seyferts compared to luminous ones.

High inflow detection rates suggest feeding of the AGN.

Outflow velocities in Seyfert 1s are significantly larger.

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 10^9.9 < L_IR/L_sun < 10^11, or, equivalently, star formation rates (SFR) of ~0.4 -- 9 solar masses per year, to attempt to isolate the source of the outflow. We find that the outflow detection rates for the infrared-faint Seyfert 1s (6%) and Seyfert 2s (18%) are lower than previously reported for infrared-luminous Seyfert 1s (50%) and Seyfert 2s (45%). The outflow kinematics of infrared-faint and infrared-bright Seyfert 2 galaxies resemble those of starburst galaxies, while the outflow velocities in Seyfert 1 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 Seyfert 1 galaxies. Another striking result of this study is the high rate of detection of inflows in infrared-faint galaxies (39% of Seyfert 1s, 35% of Seyfert 2s), 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.