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XMM-Newton Science Analysis System


evigweight (evigweight-1.8) [xmmsas_20230412_1735-21.0.0]

Pros and cons

Advantages: exact, easy to use (only one ARF), can deal with any complex spatial variation of the source.

Drawbacks: degradation of the statistical quality:

  $\displaystyle \Delta O'(I)/O'(I) \; = \;
\sqrt{\langle{w_{j}^{2}}\rangle}/\langle{w_{j}}\rangle \;
\Delta O(I)/O(I)
$ (11)
from Eq.5 and 6. This is not a problem if the effective area is not varying much in the region considered ( $\sqrt{\langle{w_{j}^{2}}\rangle}/\langle{w_{j}}\rangle\sim 1$).



XMM-Newton SOC -- 2023-04-16