XMM-Newton Announcement of Opportunity: Policies and Procedures

7.3.2 Review Process and Selection Criteria

The OTAC will review the ``Open Time'' proposals and will make recommendations on the observing program to be carried out by XMM-Newton. The following items will be taken into account during the review process:

• scientific case and justification,
• scientific merit and relevance of the proposed observation(s),
• contribution to the overall scientific return of XMM-Newton,
• duplication with performed and planned XMM-Newton and Chandra observations
• technical feasibility and exposure time estimation,
• visibility and requested observing time.

The recommendations on XMM-Newton's observing programme are made via assignation of one of three scientific priorities to every individual observation: A, B and C (A being the highest ranking). In addition, the OTAC

• is responsible for defining and resolving cases of duplication,
• has the right to recommend exposure times either for entire proposals or for individual observations,
• decides about the acceptance of observing constraints.

For efficient timelining of observations, the scientific scheduling software needs to work from a pool of observations which significantly overfills the time available. Thus, the recommendations mentioned above will take into account the provision of the necessary oversubscription in the data base of planned observations. Priority A and B targets are of major scientific importance and will be scheduled with highest priority. Priority C targets are used as ``fillers'' and have a significant lower likelihood to be finally scheduled. The fraction of priority C targets which are expected to be observed can be estimated from the statistics in previous AOs. The interested scientist may consult the ``XMM-Newton Quarterly Status Report'' in the XMM-Newton web site.

It is planned that (without further review by the OTAC) A and B targets will be transferred to the next observation period, if their successful observation should not be possible during the current one. ``Fixed-Time'' proposals from this AO which are no longer technically feasible in the following observing period will not be carried forward. C priority targets that have not been observed by the end of the AO will not be transferred into the following AOs and therefore will be freely available for new proposals. However, it is emphasized that, for operational and technical reasons, no guarantee can be given that any particular observation will, in fact, be executed.

Titles and abstracts of accepted proposals will be made publicly available.