Luminosity function of X-ray-selected AGNs

The spectra of individual X-ray sources are analyzed using a Bayesian methodology with a physically realistic model to infer the posterior distribution of the hydrogen column density and intrinsic X-ray luminosity.

We develop a novel non-parametric method that allows us to robustly infer the distribution of the AGN population in X-ray luminosity, redshift, and obscuring column density, relying only on minimal smoothness assumptions. Our analysis properly incorporates uncertainties from low count spectra, photometric redshift measurements, association incompleteness, and the limited sample size. We find that obscured AGNs with N_H_>10^22^/cm2 account for 77_-5_^+4^% of the number density and luminosity density of the accretion supermassive black hole population with L_X_>10^43^erg/s, averaged over cosmic time.