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especget (especget-1.54) [xmmsas_20230412_1735-21.0.0]


especget is a one-stop task which produces all the files necessary for the spectral fitting of an XMM source. The task allows the user to produce a source spectrum, background spectrum and the OGIP-compliant (spectral fitting within a single procedure.

The essential input parameters are the name of the XMM events table and a selection expression for the source and background areas, e.g. srcexp="((DETX,DETY) IN circle(572,-635,1340))"
backexp="((DETX,DETY) IN circle(2572,-1635,1340))". The minimum selection required in the source and background expressions is the spatial region, which may be specified in sky (X/Y) or detector coordinates. Other selections are defaulted as shown in Table 1. These defaults may be further restricted by including additional selections for these quantities in the input expressions, e.g. srcexp="((DETX,DETY) IN circle(572,-635,1340))&& PATTERN==0". NB: The source and background expressions should use the same pattern and flag selections. The expressions must be compliant with the selectlib standard.

The metatask especget runs the tasks evselect, arfgen and rmfgen. It also calculates the size of the source and background areas, a job normally performed by the task backscale but here achieved by calling arfgen directly. For more details of the processing performed by these tasks please see their respective user documentation.

The end result is a set of files which can be used directly in a spectral fitting program (see section 3.3).

Table 1: Default event selections
Parameter Camera
PATTERN 0–12 0–4
$^{a}$ The selection #XMMEA_EM represents a conglomerate of flags; see evatt.

XMM-Newton SOC -- 2023-04-16