XMM-Newton Announcement of Opportunity: Policies and Procedures

3.4 Discretionary Time

The XMM-Newton Project Scientist can grant ``Discretionary Time'', which is $\sim$5% of the XMM-Newton observing time.

Unanticipated Target of Opportunity observations are executed in the ``Discretionary Time'' of the Project Scientist. The Project Scientist can use his ``Discretionary Time'' to increase observing time of accepted targets. This does not impact on the data rights nor on the proprietary period of the observation.