Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://xmm.vilspa.esa.es/sas/8.0.0/doc/eregionanalyse/node20.html
Дата изменения: Fri Oct 24 21:40:49 2008 Дата индексирования: Sat Oct 17 00:21:36 2009 Кодировка: Поисковые слова: arp 220 |
![]() |
(1) |
where is the counts within the source region,
is the total background
counts and
,
are the area of the source and background
regions respectively.
The background is simply scaled by the respective box areas; no vignetting correction of any sort is made. The error is calculated from photon statistics as:
![]() |
(2) |
NB: This is only reliable for circular source regions, see section 5.2.8