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XMM­Newton CCF Release Note
XMM­CCF­REL­24
OM PSF
R. Much
October 3, 2000
1 CCF components
Name of CCF VALDATE List of Blocks
changed
CAL VERSION XSCS flag
OM PSF1DRB 0003 2000­01­01T00:00:00 PSF­U No
PSF­B No
PSF­V No
PSF­UVW1 No
PSF­UVM2 No
PSF­UVW2 No
PSF­WHITE No
PSF­MAGNI No
2 Changes
First release
The CCF file psf1drb describes the OM PSF of the non­dispersive filter elements at different
count to framerate ratios (CFRR).
The current analysis is limited by a number of factors, these include:
ffl only preflight gaussian approximations are used,
ffl only one PSF per filter is available, i.e. the CFRR dependence is not yet parametrized.
ffl the inflight adjustment of the focus is not reflected in the current release of the om psf1drb
ffl no data for the UVW2 PSF were available from CSL. The UVW2 PSF is assumed to be
identical to the UVM2 PSF.
1

XMM­Newton CCF Release XMM­CCF­REL­24 Page: 2
Before an OM inflight PSF can be provided a correct description of the combined effect of
instrument PSF and coincidence loss must be found. It was found that coincidence losses (detector
linearity) and the PSF shape are tightly coupled. Further analysis is required before a combined
description can be provided.
We expect the psf1drb file to be updated, once further progress in the PSF/coincidence loss
calibration is made.
3 Scientific Impact of this Update
First release
4 Estimated Scientific Quality
While the current approximation is sufficiently good at low count rates (approximately less than 10
cts/sec), the PSF description becomes more and more inaccurate with increasing count rate.
5 Acknowledgements
Thanks to OM team members, especially Alice Breeveld (MSSL) for her input.