Документ взят из кэша поисковой машины. Адрес оригинального документа : http://xmm.vilspa.esa.es/docs/documents/CAL-SRN-0088-1-0.ps.gz Дата изменения: Fri Sep 21 15:01:52 2001 Дата индексирования: Mon Oct 1 22:02:29 2012 Кодировка: Поисковые слова: mercury program

XMM­Newton CCF Release Note
XMM­CCF­REL­88
RGS Line Spread Function -- New Scatter Parameters
C. Erd
September 5, 2001
1 CCF components
Name of CCF VALDATE List of Blocks
changed
CAL VERSION XSCS flag
RGS1 LINESPREADFUNC 0004 1999­01­01T00:00:00 LASCAT xmmsas 20010329 1900 NO
RGS2 LINESPREADFUNC 0004 1999­01­01T00:00:00 LASCAT xmmsas 20010329 1900 NO
2 Changes
The parameters of the r.m.s. surface roughness as a function of wavelength was changes according
to the values in [1].
3 Scientific Impact of this Update
The cross­dispersion LSF had an additional level of scattered light, which caused an underestimation
of the inter­order scattered light by the response see [1, Figure 3]. This light is distributed in the
PI versus BETA plot between the orders, at constant BETA (mimicking an insufficient calibration
of the response of the CCD).
This effect was included in the response as from rgsrmfgen 0.45.3. Therefore a modification
of the large angle scattering parameters was necessary.
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XMM­Newton CCF Release XMM­CCF­REL­88 Page: 2
4 Estimated Scientific Quality
The impact of this change on the effective area is only a few percent. But depending on the spectrum
of the source, additional flux across orders occurs for harder spectra, which previously resulted in a
net underestimate of the modeled counts, due to enhanced 'bleeding' of the higher orders into low
order spectra.
Hence improvements of the spectral modeling are dependent of the spectrum of the source in
question. See [1] for a detailed description of the effect of the change.
References
[1] John Peterson Jean Cottam. The Cross­Dispersion Distribution of the Large­
Angle Scattered Light. RGS­COL­CAL­01004, Columbia University, 2001.
http://xmm.astro.columbia.edu/cal files/cal01004.ps.