XMM SSC (Survey Science Centre) pages

http://xmmssc.irap.omp.eu (includes documentation on catalog columns)

http://xmm-catalog.irap.omp.eu (webserver for the catalogue)

http://xmm-ssc.irap.omp.eu (outreach website)

http://xmm-ssc.irap.omp.eu/claxson (citizen science website)

4XMM-DR12 data tables

4XMM-DR12 footprint (MOC files)

MOCs for individual observations in fits format can be downloaded from this website (identified through their OBSIDs). Additionally, the MOC covering the whole of 4XMM-DR12 field is available here.