XMM-Newton Science Analysis System
arfgen (arfgen-1.66.4) [xmmsas_20050815_1803-6.5.0]
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These modes are treated as a special case within arfgen. Regardless of
the spatial region used to extract the spectra the source is assumed
to be located at the position DETX=0, DETY=0 and the vignetting
correction is applied assuming a point source at this position.
No encircled energy correction is applied to the ARF and bad pixels
or columns are not corrected for. This can lead to 10% errors in the
flux calculated during spectral fitting. One solution is to use a
large source region to make sure that most of the flux is collected,
although this naturally increases the background in the
source spectrum.
In Timing mode it is recommended to take the full range of RAW-Y when
extracting an EPIC-pn spectrum (in MOS the RAW-Y information is not
present). It can be useful to take a restricted RAW-Y range in Burst
mode to exclude contamination from the on-axis source. In this case
arfgen
scales the ARF proportionately to the range selected.
Such a scaling is not applied for Timing mode data.
XMM-Newton SOC/SSC -- 2005-08-16