XMM-Newton Science Analysis System . ... Meta Index / Home Page / Description / General overview The selection of events prior to product extraction is carried out by the first stage of evselect . This processing step is driven by a boolean expression, i.e., events for which the expression evaluates to ``true'' are included in the subsequent product generation. The selection expression to be applied to the data is displayed in the xmmselect main window and is editable at all times. ...