The purpose of the XMM-ESAS package is to provide the tools required for the analysis of spectra and images of extended (relative to the instrumental PSF) diffuse emission. Its primary functions are to 1) measure, construct, and remove several different non-cosmic background components, 2) provide a relatively automated method for reducing extended diffuse data, and 3) provide a means for mosaicking images of extended emission (including background subtraction, exposure correction, and inter-instrument normalization).
The XMM-ESAS package before you consists of a number of SAS tasks with various functionalities. Most of these SAS tasks are direct inclusions of FORTRAN routines, while others are SAS FORTRAN versions of what had been perl scripts. If you should have some special circumstance not covered by the existing routines, you can probably accomplish what you need using basic SAS functions. On the other hand, if there is something nifty that you would like to accomplish that can't currently be done, please contact us with suggestions, as we are always open to adding new functionalities. A complete alphabetical list of ESAS routines appears at the beginning of Appendix A. The next sections contain the step-by-step instructions for using each of the routines in the order they need to be applied.