Linked observations require special arrangements to be made to ensure a fast turnaround for the test data analysis. Because the XMM SOC will operate with only very few staff astronomers, user support will under normal circumstances be restricted to normal working hours. Therefore, it will be the observer's responsibility to analyse the test data before the main observing run, which may require his/her presence during/after the test observations. Moreover, linked observations cannot be entered during proposal submission via XRPS as ``fixed-time'' in order to give the SOC maximum flexibility in selecting the optimal interval between the test and the main observation.
Proposals requesting linked XMM observations will therefore need a very strong specific scientific justification. In general, proposals for linked XMM observations are discouraged.