The ultimate XMM-Newton extragalactic survey (XXL) is the medium deep 50 deg2 X-ray survey (with completeness to 10 ks) which consists of two equal-sized fields: LSS (Northern – equatorial) and BCS (Southern), fig. 1 and 2. The XXL international Consortium is a collaboration of nearly 100 scientists from 50 different institutions. See details on the official web-page.
The XXL project is uniquely powerful. It is the largest existing XMM-Newton programme, and provides a sample of about 20000 X-ray sources, the great majority being Active Galactic Nuclei (AGN). Both XXL fields are fully covered in optical (CFHTLS/BCS) and infrared (Spitzer/IRAC) bands; the LSS field also has a uniform K-band data coverage. These data, together with the ultraviolet data from the GALEX satellite, extensive radio survey data and spectroscopic follow-ups, provide an exceptional basis for a multiwavelength investigation of the evolution of AGN over cosmic time both as individual objects and as constituents of the large-scale structure. The full information about the multiwavelength coverage of the XXL survey is available here.
The XMM-LSS field occupies an area of 11.1 sq. deg. and is located in the center of the Northern XXL field (2h14m<R.A.<2h30m; -6d25m<Dec<-2d35m, J2000.0]. It is covered by see fig. 3. The XMM-LSS full exposure field contains 6342 sources detected in the soft (0.5-2 keV) and/or hard (2-10 keV) bands down to a detection likelihood of 15. This corresponds to the following flux limits (50% detection probability): F0.5-2keV= 3•10-15 erg/s/cm2 and F2-10keV= 1•10-14 erg/s/cm2, over nominal survey pointings.
The XMM-LSS field is covered by optical wavelength: CFHTLS, infrared: Spitzer/IRAC and MIPS, near-infrared UKIDSS, and ultraviolet GALEX. The multiwavelength catalog of sources in XMM-LSS is public, seeCDS and the catalog description paper by Chiappetti et al. (2013). The set of the photometric redshifts for the XMM-LSS catalog is also available in CDS, see also Melnyk et al. 2013 and Photometric redshift calculation for AGN page.