This task creates model particle background spectra and images (if selected with a non-zero energy range) for the selected region from the intermediate files produced from pn-spectra. The resultant image is in detector coordinates. The resultant image is in detector coordinates which is transformed into sky coordinates by the perl script rot-im-det-sky. pn_back creates a QDP plot file which shows the source and model background spectra for the observation. Any enhancement of the data over the particle background model at higher energies probably indicates residual soft proton contamination, unless there are really hard and bright sources in the field.
Warning and requirements: pn_back is part of the esas package integrated into SAS, but it is limited to work within the esas data reduction scheme. This is specially true wrt the structure and names of the input files. In particular, pn_back assumes that another task from the package, pn-spectra has been successfully run for the exposures to be used.
