Chandra Deep Field South AGN Spectral Properties Catalog

The authors do not find hints of a correlation between the spectral index Gamma and the intrinsic absorption column density N_H. They then investigate the absorption distribution for the whole sample, deriving the N_H values in faint sources by fixing Gamma to be 1.8. The authors find that the fraction of absorbed sources (with N_H > 10²² cm^-2) in the sample is constant (at the level of about 75%) or moderately increasing with redshift.

Finally, they compare the optical classification to the X-ray spectral properties, confirming that the correspondence of unabsorbed (absorbed) X-ray sources to optical type I (type II) AGN is accurate for at least 80% of the sources with spectral identification (1/3 of the total X-ray sample). This table was created by the HEASARC in August 2007 primarily based on <a href="cdsarc.cds.unistra.fr/ftp/cats/J/A+A/451/457">CDS Catalog J/A+A/451/457</a> file table1.dat.

The positions of the X-ray sources were taken from <a href="cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/139/369">CDS Catalog J/ApJS/139/369</a> (Giacconi et al. 2002), except for that of source number 901 which was taken from Table 5 of Szokoly et al. (2004, ApJS, 155, 271). This is a service provided by NASA HEASARC .