Physical properties of the CDFS X-ray sources through fitting spectral
  energy distributions
  The physical parameters of galaxies and/or AGNs can be derived by fitting
their multi-band spectral energy distributions (SEDs). By using CIGALE code, we
perform multi-band SED fitting (from ultraviolet to infrared) for 791 X-ray
sources (518 AGNs and 273 normal galaxies) in the 7 Ms Chandra Deep Field-south
survey (CDFS). We consider the contributions from AGNs and adopt more accurate
redshifts than published before. Therefore, more accurate star formation rates
(SFRs) and stellar masses (M$_*$) are derived. We classify the 518 AGNs into
type-I and type-II based on their optical spectra and their SEDs. Moreover, six
AGN candidates are selected from the 273 normal galaxies based on their SEDs.
Our main results are as follows: (1) the host galaxies of AGNs have larger
M$_*$ than normal galaxies, implying that AGNs prefer to host in massive
galaxies; (2) the specific star formation rates (sSFRs) of AGN host galaxies
are different from those of normal galaxies, suggesting that AGN feedback may
play an important role in the star formation activity; (3) we find that the
fraction of optically obscured AGNs in CDFS decreases with the increase of
intrinsic X-ray luminosity, which is consistent with previous studies;(4) the
host galaxies of type-I AGNs tend to have lower M$_*$ than type-II AGNs, which
may suggest that dust in the host galaxy may also contribute to the optical
obscuration of AGNs.
