XMM RPS Users' Manual

   
Default vs. non-default XMM observations

For XMM's X-ray instruments we highlight in the tables in §§ 5.3.3.1, 5.3.3.2 and 5.3.3.3 (in boldface characters) those modes of instrument operation that are strongly recommended for use during AO-1. The use of the other modes is discouraged, as the order of mode commisioning and calibration depends on the complexity and the foreseen need of these modes. Therefore, the necessary SOC support is not always possible and the required calibration accuracy may not be reached, at least in the early mission phases.

  

Figure: Sequence of OM science windows covering the FOV in an imaging mode observation. Figure prepared by D. Lumb ( XMM SOC).

Non-default mode OM observations in AO-1 are in general strongly discouraged. For such, a special scientific justification is required. Note that a number of OM default configurations has been established, which are offered as such in XRPS. Descriptions of these can be found in § 5.3.3.5 and in the OM default configurations section of the UHB. An example for an OM default configurations observation is presented in Fig. 4. Each panel displays a $17'\times17'$FOV centred on the nucleus of M101. The centre of the FOV is always covered by a small science window. In the case of imaging mode observations as shown in the figure, this is an imaging mode window, while for a fast mode default configuration there would be a ( $12''\times11''$) fast mode window at the centre. In addition, a second window, which is in all cases operated in imaging mode, is defined. A default mode observation consists of five sub-exposures, with that second imaging window first covering the central part of the FOV, then one outer quadrant and so on, until almost the entire (the limit is for practical reasons is 92%) OM FOV has been imaged. Except for the total FOV (upper left), each panel highlights the sky coverage of one of the 5 sub-exposures comprising an OM default configuration exposure. The exposure time entered in the XRPS form sheets refers to one sub-exposure so that each point on the sky will be observed as long as specified by the user's entry. At the centre of the FOV the total integration time will thus be 5 times as long, because this location will constantly be covered by a (small) science window (as best visible in the middle and lower panels).

Note: In case users should nevertheless decide to conduct non-default OM observations, it is their responsibility to obtain all necessary information and to fill out all appropriate XRPS forms correctly. Since there are no adequate defaults for observations with the OM grisms including a fast mode window to monitor the zeroth order image of the target, this case is explicitely explained in § 5.3.3.7.