The evolution of the hard X-ray luminosity function of AGN

We present new observational determinations of the evolution of the 2–10 keV X-ray luminosity function (XLF) of active galactic nuclei (AGN). We utilize data from a number of surveys including both the 2 Ms Chandra Deep Fields and the AEGIS-X 200 ks survey, enabling accurate measurements of the evolution of the faint end of the XLF. We combine direct, hard X-ray selection and spectroscopic follow-up or photometric redshift estimates at z 50 per cent of black hole growth takes place at z > 1 , with around half in L_X < 10^(44) erg s^(−1) AGN