Explaining the Hard Excesses in AGN

TL;DR

This paper demonstrates that relativistically blurred disc reflection models can explain the high-energy 'hard excesses' observed in certain active galactic nuclei, challenging the notion that complex absorption is the sole explanation.

Contribution

It shows that disc reflection models can successfully reproduce high-energy spectra in AGN, providing an alternative to absorption-based explanations.

Findings

Disc reflection models fit the observed spectra of NGC 1365, 1H 0419-577, and PDS 456.

The behavior of NGC 1365 and 1H 0419-577 aligns with previous reflection interpretations.

Reflection models can account for the hard X-ray excesses without invoking complex absorption.

Abstract

A common model invoked to describe the X-ray spectra of active galaxies includes a relativistically blurred reflection component, which in some cases can be the dominant contributor to the received flux. Alternative interpretations are often based around complex absorption, and to date it has proven difficult to determine between these two viable models. Recent works on SUZAKU observations of the active nuclei in NGC 1365, 1H 0419-577 and PDS 456 have found the presence of strong X-ray emission at high (~10-50 keV) energies, referred to as 'hard excesses', and it has been claimed this emission cannot be explained with simple disc reflection models. Here we investigate the high energy emission in these sources by constructing disc reflection models and show that they can successfully reproduce the observed spectra. In addition, we find the behaviour of NGC 1365 and 1H 0419-577 in these observations to be broadly consistent with previous work on disc reflection interpretations.