Spectral curvature values for AGN sample

Sources with obscuring column densities higher than 10^24^atoms/cm^2^, called Compton-thick (CT) AGNs, can be identified by excess X-ray emission at ~20-30keV, called the 'Compton hump'. We apply the recently developed Spectral Curvature (SC) method to high-redshift AGNs (2<z<5) detected with Chandra.

This method parametrizes the characteristic 'Compton hump' feature cosmologically redshifted into the X-ray band at observed energies <10 keV. We find good agreement in CT AGNs found using the SC method, and bright sources fit using their full spectrum with X-ray spectroscopy. In the Chandra Deep Field-South, we measure a CT fraction of 17^+19^_-11_% (3/17) for sources with observed luminosity >5x10^43^erg/s.