Bibcode
Streblyanska, A.; Bergeron, J.; Brunner, H.; Finoguenov, A.; Hasinger, G.; Mainieri, V.
Bibliographical reference
Nuclear Physics B Proceedings Supplements, Volume 132, p. 232-235.
Advertised on:
6
2004
Citations
14
Refereed citations
12
Description
We present first results of the X-ray spectral analysis of 500 ksec deep
survey images obtained with XMM-Newton on the Chandra Deep Field South
(CDFS). Statistical distributions of spectral index and intrinsic
absorption are derived for a sample containing 70 sources with a count
limit of 100 (flux limit in the 2-10 keV band of
8.9×10-16 erg cm-2s-1), of which
44 sources have had redshifts identified. We observe a spatial
separation between the type-1 and the type-2 AGN in diagnostics
involving different X-ray parameters. Using the subsample with known z,
we show that this separation between the AGN populations is a
consequence of different absorption column densities. The two
populations have the same average spectral index,
<Γ>=2+/-0.1. We present integrated spectra for the most
distant type-2 QSO which shows strong X-ray absorption and a clear soft
excess; we obtained the best fit for this object with a scattering
model. We also confirm a progressive hardening for the combined integral
spectra for faint objects which at first was noted by [Proceedings of
the XXI Moriond Astrophysics Meeting (2001)]. Our results show a clear
evolution of decrease of <Γ> with decreasing flux in the
hard 2-10 keV band. However, we detect not only a regular increase in
<Γ> for different subsamples of fluxes compared to Chandra
results, but also a discrepancy of the values within our own data set,
if we fitted in the different energy bands.