XMM-Newton Science Analysis System


xmmselect (xmmselect-2.67) [xmmsas_20230412_1735-21.0.0]

Product extraction

This is the area at the bottom of the main window and consists of seven horizontally arranged buttons labeled Filtered Table, Fix Expression, Image, Histogram, OGIP spectrum, OGIP Rate Curve, and OGIP Spectral Products respectively. Pushing either of these will trigger the following actions:

1. Execution of evselect with the selection expression in the top expression entry field. Before evselect is actually executed, its parameter dialog is presented which gives the user full control over the product extraction process, i.e., all of evselect's parameters (e.g. bin size for rates curve extraction, name of output data set, etc.) can be altered.
2. Accumulation of the respective product with a default name
3. Except for event lists, execution of a product displayer (either dsplot or imgdisplay) with the name of the generated product

A prerequisite to the extraction of images, histograms, spectra, and rate curves is the selection of data set columns which define the primary product axes (see above). This is done with the check buttons left to each push button in the middle. The leftmost check button column corresponds to the image extraction. Two and only two data set columns can be selected which defines these columns as image axes. When a column is selected in this way the associated check button will be labeled with either of the letter “X” or “Y” when being pushed. “X” is the axis which is displayed horizontally by imgdisplay. The attempt to select a third column will result in the last selected one getting unselected again. Trying to perform an image extraction without a prior column selection will result in an error condition. For histogram, spectrum, and rates curve extractions the user has to select one and only one data column with the rightmost check button column. These act as “radio” buttons, i.e. pushing a button will undo the previously made choice (if any has been made yet). As for images, trying to extract a histogram, spectrum or rates curve without a prior axis selection will lead to an error condition.

If an image, histogram, spectrum or rate curve has been successfully generated and displayed, the user can define one and two dimensional regions which xmmselect will translate into a proper boolean selection expression for a subsequent refined product generation.