cheese runs source detection (using the SAS task edetect_chain) on full-field images and creates cheese masks from the output. cheese produces the event, exposure, and mask images that are required in a user-selected energy band. Running cheese is not required if only the spectral files with all counts including point sources are required, or if excluding point sources is not of interest.
Warning and requirements: cheese is part of the esas package, integrated into SAS, but it is limited to work within esas data reduction scheme. This is specially true wrt the structure and names of the input file structure and names. In particular, cheese assumes that other tasks from the package, mos-filter, or pn-filter, have been successfully run for the exposures to be used.