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: http://xmm.vilspa.esa.es/sas/8.0.0/doc/omgchain/node22.html
Дата изменения: Wed Oct 22 17:34:32 2008 Дата индексирования: Tue Aug 18 15:07:50 2009 Кодировка: Поисковые слова: rigel |
The OM-grism photometric accuracy and spectral resolution
is under investigation. In any case the spectral resolution
cannot be better than 8 pixels ( Å for the visual grism
and
Å
for the UV).
The correction for coincidence loss is not applied currently because omgchain deals with extended sources. The reliable coincidence-loss correction method for extended sources is not developed yet. However, for faint to moderately bright spectra the effect should be less than 10%. For spectra affected by the strongly visible modulo-8 patterns, where coincidence loss is important, the extracted spectra are unreliable.
Some zero- and first-order spectra may overlap (see, e.g. Fig.7). This situation is currently not treated, and the user should be aware of such a possibility. In such cases zero-order images may cause inappropriate scaling of the output plot (Fig.8).
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XMM-Newton SOC/SSC -- 2008-10-22