The SAS task epreject allows the investigator to extend possible EPIC pn data analysis down to the softest energies (120 eV for image analysis of imaging exposures). Hence its main applications will be in the study of soft X-ray sources. Based on the intended type of science, the user needs to decide if the additional data reduction steps are worthwhile to be applied for a specific EPIC pn exposure.
The task epreject performs different actions for imaging and timing mode data which are described below in § 188.8.131.52.1, § 184.108.40.206.2 and § 220.127.116.11.3
Note: The suppression of the low-energy detector noise in EPIC pn imaging mode data was done by default by the task epreject up to SAS v12.0. The recommendation was to make use of it through the task epchain. After SAS v12.0, this functionality of epchain to make use of epreject was disabled. However the epreject functionality to suppress low-energy detector noise can still be invoqued by using the task epproc (as described in the following section § 18.104.22.168.1). In addition, the task epproc can now invoque an alternative task which implements a new method to handle the suppression of the low-energy detector noise, the task epnoise. It is planned that in the near future, the task epnoise will become the default and will replace the functionality of epreject for removing the low-energy detector noise.