Description

This task is designed to analyse a region within an XMM image. It calculates values such as a source centroid, optimum extraction radius, source counts and count rate etc. All values are written to standard output where they may be accessed by a calling script. The centroid, source counts and optimum extraction region are also returned in output parameters where they may be picked up by a calling task. A summary of the output quantities is given in Table 1.

**Table 1:** **Output quantities**
Value	Units	Output Parameter
Source counts	counts	srccnts
Counts per image pixel	counts/pixel	-
Exposure time	seconds	-
X centroid	det or sky pixels	xcentroid
Y centroid	det or sky pixels	ycentroid
Background centre	det or sky pixels	-
optimum radius	det/sky pixels	optradius
optimum ellipse X radius	det/sky pixels	optellipxrad
optimum ellipse Y radius	det/sky pixels	optellipyrad
optimum ellipse rotangle	degrees	optelliprot
encircled energy factor	-	-
Total source counts $^{a}$	counts	-
Total source count rate	counts/s	-
Statistical upper limit	counts/s	-