---
author:
- 'C. Ricci , S. Paltani , H. Awaki , P.-O. Petrucci , Y. Ueda , and M. Brightman'
bibliography:
- 'BaldwinI.bib'
date: 'Received; accepted'
title: 'Luminosity-dependent unification of Active Galactic Nuclei and the X-ray Baldwin effect'
---

Introduction
============

The observational signatures of reprocessed radiation in the X-ray spectra of Active Galactic Nuclei (AGN) are mainly two: a Compton hump peaking around 30keV and a fluorescent iron K$\alpha$ line. While the Compton hump is produced only if the reprocessing material is Compton-thick (CT, $N_{\rm\,H}\gtrsim 10^{24}\rm\,cm^{-2}$), the iron K$\alpha$ line is created also in Compton-thin material (e.g., [@Matt:2003fk]). The iron K$\alpha$ line is often observed as the superposition of two different components: a broad and a narrow one. The broad component has a full width at half-maximum (FWHM) of $\gtrsim 30,000\rm\,km\,s^{-1}$, and is thought to be created close to the black hole in the accretion disk (e.g., [@Fabian:2000uq]), or to be related to the presence of features created by partially covering warm absorbers in the line of sight (e.g., [@Turner:2009kx], [@Miyakawa:2012fk]). While the broad component is observed in only $\sim 35-45\%$ of bright nearby AGN (e.g., [@de-La-Calle-Perez:2010fk]), the narrow ($\mathrm{FWHM}\sim 2,000\rm\,km\,s^{-1}$, [@Shu:2010zr]) core of the iron line has 