XMM-Newton Users Handbook

3.3.7.4 EPIC background and its importance for extended sources

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, prepared by the Background Working Group, 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 released by the Background Working Group to help the user in the analysis of extended sources.

Currently available products are

• XMM-Newton Extended Source Analysis Software package, XMM-ESAS,
  allowing the user to model the quiescent particle background both spectrally and spatially for the EPIC detectors. As of version 9.0, XMM-ESAS is part of the Science Analysis Software (SAS).
• XMM-Newton blank sky background event files for the 3 EPIC instruments, in Full Frame and Extended Full Frame (PN only) modes, constructed using a superposition of pipeline product data from the 2XMM (see § A.3.1) reprocessing of many pointed observations. Users can request tailored blank field event lists from the EPIC Background Blank Sky Products Request Form.
• Filter Wheel Closed data:
  The stacked collections of Filter Wheel Closed (FWC) data are available for the MOS and pn cameras.

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).