Research in Astronomy and Astrophysics Fe Kα line profile in AGNs: average shape and redshift

Abstract We collect a sample of 381 (271 type I) active galactic nuclei (AGNs) with XMM-Newton observations for an analysis of the dependence of Fe Kα profiles on redshifts to test the potential cosmological evolution of spins of supermassive black holes (SMBHs). The sample spans a redshift range of z = 0.0008 − 4.76, which allows us to rebin the sample into 7 redshift groups. Phenomenological analysis of the Fe profile suggested that the line width (σ) of the narrow or broad Fe line does not show significant changes in redshift range z < 0.3. Using a physical model, we significantly detect a narrow Fe Kα line at 6.4 keV with an average equivalent width (EW) = 160 eV except for the two largest redshift bins. The EW of the Fe line does not show significant changes. We also find a relativistic broad line in three redshift bins (z < 0.116, 0.056 < z < 0.12 and 0.12 < z < 0.3) with an average EW = 522 eV