As the variable EPIC background is especially important for extended sources, the user is strongly advised to make use of previous XMM-Newton observations to estimate the ratio between expected target emission and EPIC background. The discussion of the background effects on the analysis of extended sources that even might fill the whole EPIC field of view is critical.
The Background Analysis page provides an overview on all sources of background analysis and modelling, pointing out the recommended guideline for background treatment by the EPIC consortium. It also lists products aimed at helping the user in the analysis of extended sources.
Currently available products are
Suggestions and caveats on the analysis of extended sources with the EPIC cameras have also been addressed in a SAS workshop presentation (available from the SAS Workshop page). Readers are referred to the EPIC Background Analysis page for an extensive description of the properties of the EPIC background, links to blank field and filter wheel CLOSED data, and data reduction and analysis tools.
European Space Agency - XMM-Newton Science Operations Centre