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 new class of cool pixels to
be identified. These are single columns that give signals a few percent below
the values expected from their immediately 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