Evidence for ultra-fast outflows in radio-quiet AGNs: III - location and energetics

TL;DR

This study estimates the location and energetics of ultra-fast outflows in radio-quiet AGNs, showing they are likely capable of contributing significantly to AGN feedback processes.

Contribution

It provides the first constraints on the location and energetics of UFOs in a sample of radio-quiet AGNs, supporting their role in galaxy evolution.

Findings

UFOs are located within 0.0003-0.03 pc of the black hole.

Mass outflow rates are between 0.01-1 solar masses per year.

Mechanical power of UFOs can match or exceed the minimum needed for feedback.

Abstract

Using the results of a previous X-ray photo-ionization modelling of blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs observed with XMM-Newton, in this letter we estimate the location and energetics of the associated ultra-fast outflows (UFOs). Due to significant uncertainties, we are essentially able to place only lower/upper limits. On average, their location is in the interval ~0.0003-0.03pc (~10^2-10^4 r_s) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are constrained between ~0.01-1 M_{\odot} yr^{-1}, corresponding to >5-10% of the accretion rates. The average lower-upper limits on the mechanical power are log\dot{E}_K~42.6-44.6 erg s^{-1}. However, the minimum possible value of the ratio between the mechanical power and bolometric luminosity is constrained to be comparable or higher than the minimum required by simulations of feedback induced by winds/outflows. Therefore, this work demonstrates that UFOs are indeed capable to provide a significant contribution to the AGN cosmological feedback, in agreement with theoretical expectations and the recent observation of interactions between AGN outflows and the interstellar medium in several Seyferts galaxies.