1 INTRODUCTION  
2 OPTICAL DATA SELECTION AND PROCESSING  
3 X-RAY DATA SELECTION AND PROCESSING  
3.1 X-ray data reduction  
3.2 Structural analysis of the X-ray emission  
4 X-RAY SPECTRAL MODELLING  
4.1 X-ray spectral fitting  
5 RESULTS  
5.1 Nuclear morphology  
5.2 Spectral fits  
5.3 X-ray selection bias  
5.4 BPT diagrams  
6 DISCUSSION  
6.1 AGN rate in the CALIFA  
6.2 Location of X-ray AGN in the BPT diagrams  
6.3 Completeness of AGN selection criteria  
7 SUMMARY AND CONCLUSIONS