A reflection origin for the soft and hard X-ray excess of Ark 120

TL;DR

This study analyzes Suzaku X-ray data of Ark 120, demonstrating that a reflection model with both warm and cold reprocessing components effectively explains its broadband X-ray spectrum, supporting reflection as a key process in type 1 AGN.

Contribution

It provides the first detailed reflection-based interpretation of Ark 120's X-ray spectrum, emphasizing the role of blurred disc reflection in type 1 AGN without complex absorption.

Findings

Reflection model fits broadband spectrum well

Structured iron feature observed

High-energy hump consistent with reflection

Abstract

Over the last few years several models have been proposed to interpret the widespread soft excess observed in the X-ray spectra of type 1 active galactic nuclei (AGN). In particular, reflection from the photoionized accretion disc blurred by relativistic effects has proven to be successful in reproducing both the spectral shape and the variability pattern of many sources. As a further test to this scenario we present the analysis of a recent ~100 ks long Suzaku observation of Arakelian 120, a prototypical 'bare' Seyfert 1 galaxy in which no complex absorption system is expected to mimic a soft excess or mask the intrinsic properties of this key component. We show that a reflection model allowing for both warm/blurred and cold/distant reprocessing provides a self-consistent and convincing interpretation of the broadband X-ray emission of Ark 120, also characterized by a structured iron feature and a high-energy hump. Although warm absorbers, winds/outflows and multiple Comptonizing regions may play significant roles in sources with more spectral complexity, this case study adds evidence to the presence of blurred disc reflection as a basic component of the X-ray spectra of type 1 AGN.