XMM-Newton Science Analysis System


evqpb (evqpb-0.11) [xmmsas_20230412_1735-21.0.0]

Introduction

The EPIC CCD cameras on board XMM-Newton are equipped with a filter wheel system and 6 different filter setups. One of this is a CLOSED filter. Exposures taken with the filter wheel in the CLOSED position are dominated by the instrumental background and can be used to model and subtract the internal instrumental background. This is composed by:

• Electronic readout noise (at lowest energies)
• High energy particles producing charge directly in CCD and Camex
• Particle induced X-rays (continuum and fluorescent lines), generated inside the camera
• Thermal CCD noise is negliglible

Filter Wheel Closed (FWC) event lists exist and are available through the SOC web pages for EPIC-pn and EPIC-MOS for the different EPIC modes. evqpb makes use of the CCF containing only FWC event lists corresponding to EPIC-pn Full Frame (FF) Mode and EPIC-MOS Full Frame (FF) Mode. It is highly recommended not to combine event lists from different submodes since line widths and pattern fractions are slightly different for each of the EPIC readout modes.

Fig.1 shows as an example the EPIC-pn FF FWC CCF events in a 100 seconds bin light curve. The filter expression used to create this light curves is $(FLAG==0 \&\& PATTERN <= 4)$.