1 Msec Chandra Deep Field South survey

Chandra Deep Field South (CDFS) is one of the deepest hard X-ray surveys (Giacconi et al. 2001). Depending on the absolute background flux level accepted, 70-100% is resolved into discrete sources -- 5070% in the hard band. In total 349 Chandra sources have been detected in the in the 942 ks exposure of the CDFS. Using the FORS1/FORS2 spectrographs at the VLT telescopes spectroscopic redshifts were obtained for 168 X-ray sources, of which 137 have both reliable optical identification and redshift estimate (including 16 external identifications). The R<24 observed sample comprises 161 X-ray objects (181 optical counterparts) and 126 of them have unambiguous spectroscopic identification (Szokoly et al. 2004). Population synthesis models predicted a peak around z~1.4. Contrary to these predictions the distribution peaks at lower redshifts, around 0.7. The expected large number of high redshift (5 and beyond) QSOs are not found.




Fig 1: Left: Chandra ACIS-I colour image of the Chandra Deep Field South, where the red, green, and blue colours correspond to the 0.1-1 keV, 1-3 keV, and 3-7 keV energy bands, respectively. Right: XMM-Newton PN and MOS colour image of the same region. The red, green, and blue colours refer to the 0.5-2 keV, 2-4.5 keV, and 4.5-10 keV energy bands. The field sizes are about 20 x 20 arcmin and 30 x 30 arcmin, respectively.

The main characteristics of the CDFS are:



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Author: Ingo Lehmann, Date: 10/11/2004