Agreements for Joint Observations with the NRAO/GBO/LBO were made before the VLBA was reintegrated from the LBO to the NRAO.  Therefore the documentation below mentions the LBO.

If a science project requires observations with both NRAO/GBO/LBO and XMM-Newton, then a proposal may be submitted to request time on both the radio and X-ray observatories.

By agreement with the NRAO/GBO/LBO Observatories, detailed in a Memorandum of Understanding, the XMM-Newton Project may award up to 3% of NRAO/GBO/LBO open skies observing time (as an indication, this corresponded to approx. 105/82/34 hours respectively in Semester 18A).  Similarly, the NRAO/GBO/LBO Time Allocation Committee may award up to 150 ks  of XMM-Newton time per year.  The time will be awarded only for highly ranked proposals that require use of both observatories and shall not apply to usage of archival data.  Proposers should take special care to justify both the scientific and technical reasons for requesting observing time on both facilities.  It is not essential that the requested NRAO/GBO/LBO and XMM-Newton observations be simultaneous, however clear discussion of the required level of coordination is essential for evaluating feasibility.  No NRAO/GBO/LBO time will be allocated without the need for XMM-Newton time on the same target to be obtained within this AO cycle.

Establishing technical feasibility is the responsibility of the PI, who should review the XMM-Newton Calls for Proposals and the NRAO/GBO/LBO web pages.

No observations, requiring simultaneous observation with both facilities, with a reaction time of less than 2 working days from an unknown triggering date will be considered for this cooperative program.  It is the responsibility of the PI to inform both observatories immediately if the trigger criterion is fulfilled. For proposals that are approved, both observatories will perform detailed feasibility checks. Both observatories reserve the right to reject any approved observation that is in conflict with safety or mission assurance priorities or schedule constraints, or is otherwise deemed to be non-feasible.

Apart from the above, both missions' general policies and procedures currently in force for the final selection of the proposals, the allocation of observing time, the execution of the observations, data rights and publication agreements remain unchanged.

Scientists can apply for the joint program in the ``Observation Form'' of the XMM-Newton RPS.
For each observation the PI has to specify the required observing time for both observatories.
The ``Comment'' field should be used to briefly describe the NRAO/GBO/LBO instrument modes and scheduling constraints.