We present preliminary results on the properties of relativistically broadened Fe K _ { \alpha } lines in a collection of more then 100 Active Galactic Nuclei ( AGN ) observed by the XMM-Newton EPIC-pn camera .
Our main conclusions can be summarized as follows : a ) we detect broad lines in about 25 % of the sample objects .
This fraction increases to 42 \pm 13 \% if we consider only objects with more than 10 ^ { 4 } counts in the hard ( 2–10 keV ) band , and to 50 \pm 32 \% for the small sub-sample ( 6 objects ) of type 1 Piccinotti AGN with optimal XMM-Newton exposure ( at least 2 \times 10 ^ { 5 } counts in the hard band ) ; b ) we find no significant difference in the detection rate of broad lines between obscured and unobscured AGN ; c ) the strongest relativistic profiles are measured in low-luminosity ( L _ { X } < 10 ^ { 43 } erg s ^ { -1 } ) AGN ; d ) Equivalent Widths ( EWs ) associated with relativistic profiles in stacked spectra are \mathrel { \hbox { \hbox to 0.0 pt { \lower 2.365 pt \hbox { $ \sim$ } } \kern - 3.0 pt \raise 1.72 pt \hbox { $ < $ } } } 150 eV for all luminosity classes ; e ) models of relativistically broadened iron line profiles ( kyrline , [ Dovčiak et al .
2005 ] ) , which include full relativistic treatment of the accretion disk emission around a Kerr black hole in the strong gravity regime , yield an average disk inclination angle \simeq 30 ^ { \circ } , and a radial dependence of the disk emissivity profile \simeq -3 .
The distribution of EW is very broad , with \langle \log ( EW ) \rangle = 2.4 and \sigma _ { \log ( EW ) } = 1.4 .
We estimate that an investment of about 1 Ms of XMM-Newton time would be required to put these results on a sound statistical basis .