XMM-Newton Science Analysis System: User Guide

5.6.3 The class of cool pixels

Hot pixels and columns are a routine feature of CCD detectors and rgsproc takes action to exclude them from the spectra it generates. The accumulation of nearly 1 million seconds data on the bright blazar Mkn421 over the course of the mission has allowed a class of cool pixels to be identified. These are single columns that give signals a few percent below the values expected from their immediate neighbours and are only likely to be relevant when studying weak absorption features in spectra with high statistics. By default, rgsproc does not discard these data but they can be excluded using the keepcool switch as in the following example:

 rgsproc withsrc=yes srclabel=Mkn421 \
                     srcstyle=radec srcra=166.113808 srcdec=+38.208833 \
                     keepcool=no