Relativistic Broadening of Iron Emission Lines in a Sample of AGN

TL;DR

This study analyzes X-ray spectra of eight AGN to investigate relativistic effects on iron emission lines, confirming the necessity of relativistic blurring models for accurate spectral representation.

Contribution

It provides a uniform analysis of multiple AGN spectra using advanced relativistic disk models, highlighting the importance of relativistic effects in interpreting iron line features.

Findings

Relativistic blurring is essential for modeling most AGN spectra.

Different accretion disk models yield consistent results.

Relativistic effects significantly influence iron emission line profiles.

Abstract

We present a uniform X-ray spectral analysis of eight type-1 active galactic nuclei (AGN) that have been previously observed with relativistically broadened iron emission lines. Utilizing data from the XMM-Newton European Photon Imaging Camera (EPIC-pn) we carefully model the spectral continuum, taking complex intrinsic absorption and emission into account. We then proceed to model the broad Fe K feature in each source with two different accretion disk emission line codes, as well as a self-consistent, ionized accretion disk spectrum convolved with relativistic smearing from the inner disk. Comparing the results, we show that relativistic blurring of the disk emission is required to explain the spectrum in most sources, even when one models the full reflection spectrum from the photoionized disk.