XMM-Newton Users Handbook

A..3.1 The 4XMM Catalogue

New XMM-Newton catalogues are created on a regular basis. The latest 4XMM-DR11 was released in August 2021. 4XMM-DR11 contains 895 415 detections or 602 543 unique sources drawn from 12 210 XMM-Newton observations that were public by December 17th 2020 , and covers a unique sky area of 1 239 square degrees. The median flux in the total photon energy band of the catalogue (0.2-12.0 keV) is 2.3$\times$10$^{-14}$ ; in the soft energy band (0.2 - 2 keV) the median flux is $\sim\,5.2\times10^{15}\, {\rm erg cm^{-2} s^{-1}}$, and in the hard band (2 - 12 keV) it is $\sim\,1.2\times10^{-14}\, {\rm erg cm^{-2} s^{-1}}$ . About 23% of the sources have total fluxes below 1 $\times10^{-14}\, {\rm erg cm^{-2} s^{-1}}$.

About a tenth of the observations have features that may cause spurious detections (mainly the wings of bright sources and large extended emission), and it is strongly recommended to use a filter (both per source, based on the summary flag column, and per observation, based on the observation class column).

Since 4XMM-DR9, spectral energy distributions (SEDs) are provided for each of the unique 4XMM sources after cross-match with 26 archival catalogues selected to cover the largest sky coverage and widest span in wavelength from UV to radio.

The stacked catalogue (4XMM-DR11s) has been compiled from 1 475 groups, comprising 8 292 overlapping good-quality XMM-Newton observations. It contains 358,809 unique sources, 275 440 of them multiply observed.

XMM-Newton observers may find the 4XMM-DR11 amd 4XMM-DR11s catalogues useful in planning new observation proposals. Further details of each XMM-Newton EPIC catalogue, including available formats, access methods and the Catalogue User Guides, are available through links from the Catalogues home page, at:
http://xmmssc.irap.omp.eu/.
The 4XMM catalogues are described in the Astronomy & Astrophysics papers Webb et al., 2020, A&A, 641, A136, Traulsen et al., 2020, A&A, 641, A137, and Traulsen et al., 2019, A&A, 624, A77. Previous major revisions of the catalogue are also useful to understand the full content of the catalogue and their associated source product (Rosen, Webb, Watson et al., 2016, A&A, 590, A1 and Watson et al., 2009, A&A, 493, 339).

The catalogue can be retrieved from the XMM-Newton Science Archive web page in FITS or CSV format and is fully accessible through XMM-Newton Science Archive user interface.

Other useful interfaces to the 4XMM-DR11 catalogue include

IRAP catalogue server	http://xmm-catalog.irap.omp.eu/
XCATDB:	http://xcatdb.unistra.fr,
HEASARC interface:	http://heasarc.gsfc.nasa.gov/W3Browse/xmm-newton/xmmssc.html

which are particularly useful for exploring correlations with other catalogues.