The proposer has to select the proposal type ``Anticipated Target of Opportunity'' and to specify the coordinates whenever they are known in advance. For event types where the coordinates are not known in advance the PI has to use the place holder coordinates RA0 and Dec0 for each observation. TOO observations must be submitted as ``Fixed-Time'' observations, see Section 5.5.1, and require observing priority A or B, see Section 7.3.2. In the ``Trigger criteria, reaction time and observing strategy'' box of the proposal form the proposer must provide a short and clear description of what triggers the actual observation to be performed, the necessary reaction time for scheduling the observation after it is triggered and the observing strategy in particular the principal instrument and mode. For accepted proposals, this description will be made public as entered in the proposal form.
Given the nature of such events, re-scheduling of the XMM-Newton observing sequence and update of instrument modes is likely to be necessary. Consequently, the observing parameters should be provided on a best guess basis.
It is the responsibility of the PI of the TOO proposal to alert the SOC when the triggering condition is met. To avoid any conflict with an unanticipated Target of Opportunity (Section 22.214.171.124), the PI is asked to provide all necessary information and to update the observing parameters immediately after an event has occurred. In case of a conflict with other approved observations, including unanticipated TOOs (Section 126.96.36.199), the Project Scientist will decide. The basis of the decision will be the information provided, as well as the time when the information arrived at the SOC.
In contrast to all ``Guest Observer'' proposals, the OTAC can allocate observing time to the entire ``Anticipated Target of Opportunity'' proposal and not to individual observations. This offers the possibility to provide a list of candidates, without specifying which of the sources will finally be observed. For every source in a candidate list a separate observation form has to be filled-in within the RPS. For some of the candidates one may ask for zero observing time such that the total requested time in the proposal reflects the proposed observing strategy. OTAC may accept only a subset of the candidates.
XMM-Newton will perform follow-up observations of gravitational wave candidate events within the framework of a Memorandum of Understanding (MoU) among the Laser Interferometer Gravitational-Wave Observatory (LIGO) and LIGO Scientific Collaboration (LSC), the European Gravitational Observatory, Virgo Collaboration (EGO/Virgo) and XMM-Newton using XMM-Newton "Discretionary Time" (Section 3.2). The XMM-Newton project invites interested scientists from the astronomical community to participate in the analysis of XMM-Newton data obtained within the MoU. Interested scientists are asked to contact the project scientist directly.