Scaling ultraviolet outflows in Seyferts

TL;DR

This paper investigates the properties of UV outflows in Seyfert galaxies, modeling their distances and velocities to assess their potential as feedback mechanisms in active galactic nuclei.

Contribution

It models UV outflows in NGC 4051 to evaluate their ability to escape black hole gravity and discusses implications for AGN feedback across different luminosities.

Findings

Outflow velocities are near or below escape velocity.

Outflows may not be fully accelerated yet.

Higher-luminosity AGN may have more effective feedback.

Abstract

X-ray and UV absorbing outflows are frequently seen in AGN and have been cited as a possible feedback mechanism. Whether or not they can provide adequate feedback depends on how massive they are and how much energy they carry, but it depends in a more fundamental way upon whether they escape the potential of the black hole. If the outflows have reached their asymptotic velocity when we observe them, then all of these properties critically depend on the radius of the outflow: a value which is difficult to measure. The tightest limit on the distance of an X-ray warm absorber from the ionizing source is that of Krongold et al. (2007) for NGC 4051. We use NGC 4051 to model other observed UV outflows, and find that on the whole they may not provide meaningful feedback. The outflow velocities are below or just above the escape velocity of the black hole. This may be because they are not yet fully accelerated, or the duty cycle of high-velocity outflows may be small. Another possibility is that they may only provide meaningful feedback in higher-luminosity AGN, as we find a weak correlation between the ratio of outflow velocity to escape velocity and AGN continuum luminosity.