XMM-Newton Science Analysis System
evigweight (evigweight-1.8) [xmmsas_20190531_1155-18.0.0]
Advantages: exact, easy to use (only one ARF), can deal with any
complex spatial variation of the source.
Drawbacks: degradation of the statistical quality:
![\begin{displaymath}
\Delta O'(I)/O'(I) \; = \;
\sqrt{\langle{w_{j}^{2}}\rangle}/\langle{w_{j}}\rangle \;
\Delta O(I)/O(I)
\end{displaymath}](img44.png) |
(11) |
from Eq.5 and
6.
This is not a problem if the effective area is not varying much in the
region considered
(
).
XMM-Newton SOC/SSC -- 2019-06-02