The X-ray Identification Project: 

The SSC has a major responsibility towards the identification and follow-up of serendipitous X-ray sources detected in the EPIC CCD cameras, i.e. the XMM-Newton serendipitous sky survey. A full description of this project is given in Watson et al. (2001). The XID programme aims to ensure that the full potential of the XMM-Newton serendipitous source survey is achieved for the benefit of the scientific community.

The programme is exclusively based on public XMM-Newton data, or on XMM-Newton data for which the observer has granted the SSC rights to utilise serendipitous content of the data.

All the results from the programme will be publicly accessible through the XMM-Newton science archive at the SOC.

The main programme components are:


Optical imaging and spectroscopy of well-defined samples from selected XMM-Newton fields, in order to characterise their X-ray source population. Analysis of these samples will be used to establish statistical identification criteria to characterise the complete XID database.

The core programme aims to provide large enough samples to characterise XMM-Newton source populations with sample size sufficient to get 10 objects per sample even for minority objects present at the 1% level.

The core programme (at high Galactic latitudes) will be based on samples of ~1000 objects in each of 3 broad flux ranges:

FAINT ( > 10-15 erg cm -2 s -1 )
MEDIUM ( > 10-14 erg cm -2 s -1 )
BRIGHT (> 10-13 erg cm -2 s -1 )

There is a comparable programme at low galactic latitudes (PI C.Motch, Strasbourg) - but based on studies of selected regions.


More extensive optical imaging programme based on a large fraction of all XMM-Newton fields, providing the optical magnitudes and colours which are essential parameters for statistical identification.

XID data can be retrieved via the XCATDB and further information can be found on these pages about the medium sample the bright sample and the Galactic Plane sample. You can also find a number of publications here.