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 contin- uum, indicative of heavy obscuration along our line of sight (NH > 1025 cm−2 in most cases). These results 1) provide further evidence in favor of the unified scenario, and 2) indi- cate that the average obscuration of type 2 AGNs is very likely much higher than deduced by former X–ray surveys. These find- ings have important implications for the synthesis of the X–ray background.
Heavy obscuration in X-ray weak AGNs / Maiolino, R.; Salvati, M.; Bassani, L.; Dadina, M.; della Ceca, R.; Matt, G.; Risaliti, G.; Zamorani, G.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - ELETTRONICO. - 338:(1998), pp. 781-794.
Heavy obscuration in X-ray weak AGNs
RISALITI, GUIDO;
1998
Abstract
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 contin- uum, indicative of heavy obscuration along our line of sight (NH > 1025 cm−2 in most cases). These results 1) provide further evidence in favor of the unified scenario, and 2) indi- cate that the average obscuration of type 2 AGNs is very likely much higher than deduced by former X–ray surveys. These find- ings have important implications for the synthesis of the X–ray background.
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