6 Summary and outlook

We have constructed a catalogue with positions, morphology and deep BVRphotometry (B, $V_{5\sigma}\approx 25.5$ $R_{5\sigma} = 26$) of 63501 objects on an area of $31\hbox{$.\mkern-4mu^\prime$ }5 \times 30\hbox{$^\prime$ }$containing the Chandra Deep Field South. This catalogue is available to the scientific public at Centre de Données astronomiques de Strasbourg (CDS, http://cdsweb.u-strasbg.fr/ cgi-bin/qcat?J/A+A/377/442).

We have presented a first list of faint variable objects, which are supposedly mostly quasars including some Seyfert galaxies or Supernovae in late stages. Three transient sources are strongly suggestive of supernovae, but one of them had an unusually red color of .

When fully reduced, the dataset collected by the COMBO-17 survey will provide a bonanza of pseudo-spectroscopic information. We expect to classify some 50000 objects over an area of 1 deg²down to (completeness limit). Besides the classification infomation (star, galaxy or quasar) we will get spectral subclasses and high-quality redshift estimates for extragalactic sources. The full catalogue will then allow to finally classify also the variable sources and tell the redshifts of the Supernova host galaxies. It will not only provide an optical classification of the X-ray sources but also of neighboring objects in their environment.

Acknowledgements

This work was supported by the DFG-SFB 439. We would like to thank the referee, Dr. F. Mannucci for quite a detailed report which helped to improve the paper significantly.