PICONCELLI , E.

Context. X-ray extragalactic surveys are ideal laboratories for the study of the evolution and clustering of active galactic nuclei (AGN). Usually, a combination of deep and wide surveys is necessary to create a complete picture of the population. Deep X-ray surveys provide the faint population at high redshift, while wide surveys provide the...

The XXL survey currently covers two 25 deg2 patches with XMM observations of ∼10 ks. We summarize the scientific results associated with the first release of the XXL dataset, which occurred in mid‐2016. We review several arguments for increasing the survey depth to 40 ks during the next decade of XMM operations. X‐ray (z < 2) cluster, (z < 4)...