Modeling the Fe K Line Profiles in Type I AGN with a Compton-Thick Disk Wind

TL;DR

This study models Fe K line profiles in Type I AGN using a Compton-thick disk wind, revealing how such winds influence X-ray spectra and emission features without requiring direct line-of-sight absorption.

Contribution

It introduces a model of a Compton-thick accretion-disk wind to explain Fe K emission profiles in Seyfert galaxies, expanding understanding of AGN X-ray spectra.

Findings

Fe K line profiles are well described by the wind model

Neutral Fe K alpha emission likely from distant reprocessing region

Wind effects can be observed even without direct absorption

Abstract

We have modeled a small sample of Seyfert galaxies that were previously identified as having simple X-ray spectra with little intrinsic absorption. The sources in this sample all contain moderately broad components of Fe K-shell emission and are ideal candidates for testing the applicability of a Compton-thick accretion-disk wind model to AGN emission components. Viewing angles through the wind allow the observer to see the absorption signature of the gas, whereas face-on viewing angles allow the observer to see the scattered light from the wind. We find that the Fe K emission line profiles are well described with a model of a Compton-thick accretion-disk wind of solar abundances, arising tens to hundred of gravitational radii from the central black hole. Further, the fits require a neutral component of Fe K alpha emission that is too narrow to arise from the inner part of the wind, and likely comes from a more distant reprocessing region. Our study demonstrates that a Compton-thick wind can have a profound effect on the observed X-ray spectrum of an AGN, even when the system is not viewed through the flow.