HST Call for Proposals

3.7	Joint HST/XMM-Newton Observing Proposals

If your science project requires observations from both HST and the XMM-Newton Observatory, you can submit a single proposal to request time on both observatories to either the HST Cycle 24 or the XMM-Newton Cycle AO-16 review. Joint HST/XMM-Newton Proposals should be submitted to the observatory that represents the prime science facility (not to both observatories).

By agreement with the XMM-Newton Observatory, the HST TACs will be able to award up to 150 kiloseconds of XMM-Newton observing time. Similarly the XMM-Newton TACs will be able to award up to 30 orbits of HST time. The only criterion above and beyond the usual review criteria is that the project must be fundamentally of a multi-wavelength nature, and that both sets of data are required to meet the science goals. XMM-Newton time will only be awarded in conjunction with new HST observations (and should not be proposed for in conjunction with an AR or Theory Proposal). Proposers should take special care in justifying both the scientific and technical reasons for requesting time on both missions.

It is not essential that the project requires simultaneous XMM-Newton and HST observations. No XMM-Newton observations with a reaction time of less than five working days from the trigger date will be considered. Target of Opportunity (ToO) Proposals must state explicitly whether the HST observations require a disruptive ToO. No more than one disruptive ToO will be allocated per proposal. It is the responsibility of the PI to inform both observatories immediately if the trigger criterion is fulfilled.

Proposals for combined HST and XMM observations should be submitted to the observatory that represents the prime science (not to both observatories). STScI reserves the right to disallow HST observations that duplicate those in joint HST-Chandra or HST-Spitzer unless the duplications are justified in the original proposals. While there is multi-wavelength expertise in the review panels for both observatories, typically the HST panels will be stronger in IR/optical/UV science and the XMM panels in X-ray science.

Establishing the technical feasibility of the XMM-Newton observations is the responsibility of the PI, who should review the XMM-Newton Instrument Handbooks. A description of the technical information that should be included in the proposal is given in Section 9.4.3. All standard observing restrictions for both observatories apply to joint proposals. For proposals that are approved, both projects will perform detailed feasibility checks. Both projects reserve the right to reject any approved observation that is in conflict with safety or schedule constraints, or is otherwise deemed to be non-feasible.


	Joint HST/XMM-Newton Proposals must be identified in the ‘Special Proposal Types’ section of the proposal (see Section 8.10). Also, you must include technical information about the XMM-Newton observations in the ‘Coordinated Observations’ section of the proposal (see Section 9.4.3).