Explaining the hard excesses in active galactic nuclei

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 that 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, 1H 0419-577 in these observations to be broadly consistent with previous work on disc reflection interpretations. © 2010 The Authors. Journal compilation © 2010 RAS.