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Дата изменения: Thu Mar 18 23:20:18 2004
Дата индексирования: Sat Dec 22 11:37:47 2007
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Spatial analysis XMM-Newton SAS Home Page
XMM-Newton Science Analysis System


evigweight (evigweight-1.6) [xmmsas_20040318_1831-6.0.0]

Spectral analysis Description Pros and cons Home Index

Meta Index / Home Page / Description

Spatial analysis

In the same way, constructing an image $D'(\alpha,\delta)$ of the source within the energy band $E_1,E_2$ may be done by calling evselect (with withzcolumn=Y withzerrorcolumn=N) :

$\displaystyle D'(\alpha,\delta)$ $\textstyle =$ $\displaystyle \sum_{E_1 < E_j < E_2} w_j \: / \: T_{exp}$ (9)
$\displaystyle \sigma(D'(\alpha,\delta))$ $\textstyle =$ $\displaystyle \sqrt{\sum_j w_j^2} \: / \: T_{exp}$ (10)

This is directly proportional to the source brightness (no need to divide by the exposure map), except for bad pixels and CCD gaps (see Sect.3.9).


XMM-Newton SOC/SSC -- 2004-03-18