Heavy obscuration in X–ray weak AGNs

We present observations in the 0.1–100 keV spectral band of 8 Seyfert 2 galaxies, obtained by means of BeppoSAX. These sources were selected according to their [OIII] optical emission line flux, to avoid biases against obscuration on the pc scale. All sources were detected. All of them are weak X–ray emitters, and most of them are characterized by prominent iron lines at 6.4–7 keV (EW> 500 eV) and by a flat continuum, indicative of heavy obscuration along our line of sight (NH > 10 25 cm in most cases). These results 1) provide further evidence in favor of the unified scenario, and 2) indicate that the average obscuration of type 2 AGNs is very likely much higher than deduced by former X–ray surveys. These findings have important implications for the synthesis of the X– ray background.