XMM-Newton Announcement of Opportunity: Policies and Procedures


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5.6.3 Background Radiation


Background radiation affects XMM-Newton observations. Experience shows that observations aiming to detect faintest point-like sources or extended structure like clusters of galaxies, require a ``low'' background radiation level and that only about 60% of the observing time can be considered as low background radiation level. There are different observing strategies to handle the high background radiation level. Most common are:

OTAC is asked to carefully consider the discussion of the background handling and exposure time calculation in its decision.


The feasibility study of extended sources requires special attention. Proposers should consider that besides the X-ray background also the instrumental background has to be taken into account. Experience shows that in the absolute minimum proposers should provide the background count rate per unit area (count/s/cm$^2$) and the signal to background ratio required for the most critical region, i.e. the region for which the spectral analysis or deeper source detection is proposed. Proposers should also specify the energy bands to which these numbers are referring.


next up previous contents
Next: 5.6.4 Non-Standard Instrument Modes Up: 5.6 Aspects of Visibility, Feasibility, Background and Instrument Modes Previous: 5.6.2 Feasibility of Observations
European Space Agency - XMM-Newton Science Operations Centre