XMM-Newton Serendipitous Source Catalogue: 1XMM

We are pleased to announce the release of the first XMM-Newton Serendipitous Source Catalogue: 1XMM.

1XMM is the first comprehensive catalogue of serendipitous X-ray sources from the European Space Agency's (ESA) XMM-Newton observatory. The catalogue has been constructed by the XMM-Newton Survey Science Centre (SSC) on behalf of ESA. Most of the entries (> 80%) have not been previously reported as X-ray sources.

The catalogue contains source detections drawn from 585 XMM-Newton EPIC observations made between 2000 March 1 and 2002 May 5; all datasets were publicly available by 2003 January 31 but not all public observations are included in this catalogue. The catalogue contains 33026 X-ray source detections with likelihood values >8 and summary quality flag >0, together with a further 23685 detections with lower likelihood values and/or summary quality flag=0. These latter sources have lower reliability, since those with quality flag=0 are deemed to be false detections due to processing deficiencies, whilst at likelihoods below 8 the fraction of spurious sources expected on a statistical basis increases rapidly. The 33026 X-ray source detections relate to 28279 unique X-ray sources. The median flux (in the total photon energy band 0.2-12 keV) of the catalogue sources is ~3 × 10-14 erg cm-2 s-1; ~12% have fluxes below 1 × 10-14 erg cm-2 s-1.


The 1XMM catalogue, released on 2003 April 7th and designated as Version 1.0.1, is available here in FITS binary format (gzip 32MB).

The version of the 1XMM catalogue which contains revised positional errors was released on 2004 December 16th and was designated as Version 1.1.0. It is available here in FITS binary format (gzip 25MB). The catalogue is also available from:

XSA, XCAT-DB, LEDAS and HEASARC provide Web-based user interfaces allowing filtering and searching of the catalogue, and links to associated data products. The SSC Home Page, XSA, Vizier and HEASARC allow download of the catalogue file in (binary) FITS.


The User Guide contains details of the catalogue production process and content.

The User Guide for the original 1XMM catalogue (version 1.0.1) is available here, the User Guide for the revised 1XMM catalogue (version 1.1.0) is available here.

The screening user guide contains details of how the data screening was performed for the 1XMM catalogue. All component files of the screening guide are also available as a tar file (23MB).

Nomenclature and Citation

The correct nomenclature for references to sources in the catalogue is the name starting with the '1XMM' designator, as included in the catalogue itself.

Until the catalogue paper is accepted for a refereed publication, the preferred citation of the catalogue itself is:

"The First XMM-Newton Serendipitous Source Catalogue,  XMM-Newton Survey Science Centre (SSC), 2003."


The production of the XMM catalogue is a collaborative project involving the whole SSC Consortium:

The SSC team is pleased to acknowledge the contributions to the SAS software, on which the catalogue processing is based, made by ESA's Science Operations Centre staff. Significant contributions to the production of the catalogue were also made by NASA Goddard Space Flight Centre HEASARC staff resident for much of the project at the University of Leicester