Obscuration-dependent evolution of Active Galactic Nuclei

摘要: We aim to constrain the evolution of AGN as a function obscuration using an X-ray selected sample $\sim2000$ from multi-tiered survey including CDFS, AEGIS-XD, COSMOS and XMM-XXL fields. The spectra individual sources are analysed Bayesian methodology with physically realistic model infer posterior distribution hydrogen column density intrinsic luminosity. develop novel non-parametric method which allows us robustly population in luminosity, redshift obscuring density, relying only on minimal smoothness assumptions. Our analysis properly incorporates uncertainties low count spectra, photometric measurements, association incompleteness limited size. find that obscured $N_{H}>{\rm 10^{22}\, cm^{-2}}$ account for ${77}^{+4}_{-5}\%$ number luminosity accretion SMBH $L_{{\rm X}}>10^{43}\text{ erg/s}$, averaged over cosmic time. Compton-thick approximately half population, ${38}^{+8}_{-7}\%$ total. also evidence is obscuration-dependent, strongest around $N_{H}\thickapprox10^{23}\text{ cm}^{-2}$. highlight this by measuring fraction Compton-thin AGN, increases towards $z\sim3$, where it $25\%$ higher than local value. In contrast consistent being constant at $\approx35\%$, independent discuss our findings context existing models conclude observed first order side-effect anti-hierarchical growth.