Relativistic Fe K alpha line study in Seyfert 1 galaxies observed with Suzaku

TL;DR

This study analyzes Suzaku X-ray spectra of Seyfert 1 galaxies, confirming the ubiquity of relativistic Fe K alpha lines in high-quality data and exploring their relation to the reflection continuum.

Contribution

It provides the first comprehensive Suzaku-based confirmation of relativistic Fe K alpha lines as common features in Seyfert galaxies, with detailed analysis of their relation to reflection components.

Findings

Relativistic Fe K alpha lines detected in all high S/N sources.

Reflection component strength generally matches line strength.

Challenges to standard reflection models due to observed discrepancies.

Abstract

We present an analysis of a sample of Seyfert 1 galaxies observed with Suzaku. The aim of this work is to examine critically the evidence for a relativistic Fe K alpha line in the X-ray spectra of these AGN. The sample was compiled from those sources in which a relativistic component was missing in at least one XMM-Newton observation. We analysed the Suzaku spectra of these objects in order to have more constraints on the high energy emission, including the Compton reflection hump. The results show that the relativistic Fe K alpha line is detected (at >95% confidence) in all sources observed with high signal-to-noise ratio (e.g. where the counts in the 5-7 keV energy band are > 4 x 10^4). This is in agreement with the idea that relativistic lines are a ubiquitous feature in the spectra of Seyfert galaxies, but are often difficult to detect without very high quality data. We also investigate the relation between the Fe K alpha line and the reflection continuum at high energies. For most of the sample, the strength of the reflection component is consistent with that of the line. There are exceptions in both senses, however i.e. where the reflection continuum is strong but with weak line emission, and vice versa. These observations present a challenge for standard reflection models.